densest-70
刘耀文的大沙雕
钟意阿满
太阳系行星的名称，距日远近，质量大小
I 对不起,选的文章长了点.但是介绍纽约只能是长的. 。
Introduction
New York (city), the largest city in the United States, the home of the United Nations, and the center of global finance, communications, and business. New York City is unusual among cities because of its high residential density, its extraordinarily diverse population, its hundreds of tall office and apartment buildings, its thriving central business district, its extensive public transportation system, and its more than 400 distinct neighborhoods. The city’s concert houses, museums, galleries, and theaters constitute an ensemble of cultural richness rivaled by few cities. In 2000 the population of the city of New York was 8,008,278; the population of the metropolitan region was 21,199,865. 。
Located in the southeastern part of New York State just east of northern New Jersey, the city developed at the point where the Hudson and Passaic rivers mingle with the waters of the Atlantic Ocean and Long Island Sound. The harbor consists of the Upper Bay (an arm of the Atlantic Ocean) as well as the East River and the various waterways that border the city. Its harbor is one of the largest and finest in the world and is ice-free in all seasons. 。
New York has a temperate climate with annual precipitation of 1,200 mm (47 in) per year. The temperature ranges between 41°C (106° F) and –24° C (–11° F), but the Atlantic Ocean tends to moderate weather extremes in the city. It is about the same latitude as Naples, Italy. Although the Dutch founded the city in 1624 and called it Fort Amsterdam and then New Amsterdam, the English captured the settlement in 1664 and renamed it New York, after the Duke of York, who later became James II of England. 。
II
New York City and Its Metropolitan Area 。
Unlike most American cities, which make up only a part of a particular county, New York is made up of five separate counties, which are called boroughs. Originally the city included only the borough of Manhattan, located on an island between the Hudson and East rivers. In 1898 a number of surrounding communities were incorporated into the city as the boroughs of Queens, Brooklyn, the Bronx and Staten Island. The Bronx is the only borough on the mainland of the United States. Manhattan and Staten Island are surrounded by water, while Queens and Brooklyn are part of Long Island. 。
A
Queens
Queens is the largest of the five boroughs. Covering 282.9 sq km (109.2 sq mi) at the western end of Long Island, Queens is separated from Brooklyn by Newtown Creek and from the rest of the city by the East River and Long Island Sound. It stretches to the Atlantic Ocean on the south and borders Nassau County on the east. It is overwhelmingly residential and is probably one of the most ethnically diverse communities in the world. In 2000 Queens had 2,229,379 residents and was second in population only to Brooklyn among the five boroughs. 。
The neighborhoods of Queens have a strong sense of individual identity. Some are heavily industrial, like Long Island City, Maspeth, and College Point; others—like Douglaston, Forest Hill Gardens, and Kew Gardens—are suburban-style enclaves of the well-to-do. Major ethnic concentrations include the Greeks in Astoria; the Irish in Woodside; the Italians in Maspeth and Ridgewood; African-Americans in Hollis, Cambria Heights, St. Albans, and South Jamaica; and Jews in Forest Hills. Large numbers of Chinese and Koreans live in Queens, with particularly heavy concentrations in Flushing, Jackson Heights, Corona, and Elmhurst. 。
Queens is the home of Shea Stadium, Aqueduct Racetrack, the National Tennis Center, and both LaGuardia and John F. Kennedy airports. Queens hosted the World’s Fairs of 1939 and 1964. Queens has more than 6,400 acres of parkland, almost as much as the other four boroughs combined, and it has 16 km (10 mi) of beaches along the Atlantic Ocean. Queens is known for its numerous and enormous cemeteries. For example, Calvary Cemetery is the burial site of 2.5 million persons, more than any other burial ground in the United States. 。
B
Brooklyn
Brooklyn is the second largest and most populous of the five boroughs. It is located on the southwestern tip of Long Island west of Queens and situated across the Upper Bay and the East River from Manhattan. The borough has a land area of 182.9 sq km (70.6 sq mi). Brooklyn had 2,465,326 residents in 2000, more than any other U.S. city, with the exception of the entire city of New York and the cities of Los Angeles and Chicago. Indeed, as a separate municipality before 1898, it was the third largest city in the United States. 。
Brooklyn retains a strong separate identity. It has an important central business district and dozens of varied and clearly identifiable neighborhoods, including Bedford-Stuyvesant, the largest black community in the United States, and Williamsburg, Crown Heights, and Borough Park, all of which have large populations of Orthodox Jews. 。
Brooklyn is the home of such major cultural institutions as the Brooklyn Museum, the Brooklyn Academy of Music, and the Brooklyn Botanic Garden. Coney Island is well known for its beaches and amusement parks. Prospect Park, a landscaped area of broad drives and wooded hills, contains a restored carousel dating from 1912 and the Lefferts Homestead, a Dutch colonial farmhouse dating from 1783. 。
C
Staten Island
Staten Island is the third largest and least populous of the five boroughs. It is located at the juncture of Upper New York Bay and Lower New York Bay. The island is physically closer to New Jersey, to which it is connected by three bridges, than to the rest of New York City, to which it is connected only by the Verrazano-Narrows Bridge and the world-famous Staten Island Ferry. Staten Island encompasses 151.5 sq km (58.5 sq mi). The southernmost of the five boroughs, Staten Island had 443,728 inhabitants in 2000, or about 5 percent of the population of the entire city. 。
Overwhelmingly white, Staten Island has dozens of distinct neighborhoods or towns, and it has the highest proportion of single-family housing and owner-occupied housing in the city. Staten Island has many homes dating from the 17th and 18th centuries. Of special interest are the Conference House (1680), where futile peace negotiations were held between the British and American representatives in 1776 during the American Revolution (1775-1783), and the Voorlezer’s House (1695), the nation’s oldest surviving elementary school building. 。
Other attractions include the Jacques Marchais Center of Tibetan Art and the Staten Island Zoo. A memorial to Italian nationalist Giuseppe Garibaldi, who lived on Staten Island in the 1850s, is located in the borough. 。
D
The Bronx
The Bronx is the fourth largest and the northernmost of the five boroughs, and the only one on the American mainland. Even so, it is surrounded by water on three sides: Long Island Sound on the east, the Harlem and East rivers on the south, and Hudson River on the west. Encompassing 109 sq km (42 sq mi), it had 1,332,650 inhabitants in 2000. 。
Largely residential, the Bronx includes dozens of vibrant neighborhoods. Fieldston is particularly elegant, with great stone houses set among spacious lawns and privately-maintained streets, while Belmont has become the city’s most authentically Italian section. The areas along Pelham Parkway and the northern reaches of the Grand Concourse are particularly prized, because the apartment buildings are well kept and the public parks are easily accessible. City Island retains the charm of a small fishing village. 。
Parts of the Bronx, however, fell victim to decay and abandonment, especially between 1970 and 1980, when the population of the borough fell by 20 percent. The low point occurred in 1976, when future U.S. president Jimmy Carter compared the South Bronx to the bombed-out German city of Dresden after World War II (1939-1945). Since 1980 the process has again reversed and self-help groups have begun to rehabilitate most of the most devastated blocks. 。
The borough’s many attractions include the world-famous Bronx Zoo, Yankee Stadium, and the New York Botanical Garden. The Bronx also includes two of the largest middle-income housing projects in the United States. Parkchester, built between 1938 and 1942 for the Metropolitan Life Insurance Company, houses 40,000 people in apartment buildings arranged along well-planned circular drives. Co-op City is even larger, with 35 apartment towers, 236 townhouses, and more than 50,000 residents. Built between 1968 and 1970 on marshland near the Hutchinson River Parkway, it is the largest single housing complex in the nation. 。
E
Manhattan
Manhattan, or New York County, is the smallest of the five boroughs of New York City. The borough consists principally of the island of Manhattan, but also includes Governors Island, Randalls Island, Wards Island, Roosevelt Island, U Thant Island, and Marble Hill, a small enclave on the edge of the Bronx mainland. Its land area is 59.5 sq km (23 sq mi). Manhattan’s population peaked in 1910 with 2.3 million people, after which it began a slow decline to 1.4 million in 1980. Since then, the population has again begun to increase, reaching 1,537,195 in 2000. 。
Manhattan is the glittering heart of the metropolis. It is the site of virtually all of the hundreds of skyscrapers that are the symbol of the city. Among the more famous of these are the Empire State Building (1931), the Chrysler Building (1930), and Citicorp Center (1977). (The 110-story twin towers of the World Trade Center were also among New York's famous skyscrapers until they were destroyed in a terrorist attack in 2001.) Manhattan is also the oldest, densest, and most built-up part of the entire urbanized region. 。
Other noteworthy buildings include City Hall (1802-1811), a Federal-style building with French Renaissance detail; the Seagram Building (1958), an office tower clad in bronze and bronze-colored glass; and Grant’s Tomb (1897), the tomb of President Ulysses S. Grant and his wife. Notable religious structures include Saint Patrick’s Cathedral (1879), the seat of the Roman Catholic archdiocese of New York and the Cathedral of Saint John the Divine (begun 1892), the largest Gothic-style cathedral in the world. 。
Manhattan is the center of New York’s cultural life. Numerous stage and motion picture theaters are located around Broadway in Midtown, which includes Times Square. The borough is the home of prominent music and dance organizations, such as the New York City Opera Company, the Metropolitan Opera Association, the Philharmonic-Symphony Society of New York, American Ballet Theatre, and the New York City Ballet. 。
III
Population and Area 。
New York City has long been unusual because of its sheer size. Even before 1775, when its population was never more than 25,000, it ranked among the five leading cities in the colonies. It surpassed Philadelphia, Pennsylvania, by 1810 to become the largest city in the United States, and in 1830 it passed Mexico City, Mexico, to become the largest in the western hemisphere. By 1930 it was the largest city in the world. In the 1980s the metro region was surpassed in total size by Tokyo, Japan; Mexico City; and São Paolo, Brazil. Yet with 21.2 million people, the New York City region remains an urban agglomeration of almost unimaginable size. For example, in 2003, when the population of the city itself was 8.1 million, each of its five boroughs was large enough to have been an important city in its own right, with populations exceeding those of many major U.S. cities. 。
The five boroughs of New York City together cover 786 sq km (303 sq mi). The urbanized area, however, includes 28 adjacent counties in New York state, New Jersey, Connecticut, and Pennsylvania. Together, they make up the New York metropolitan region, which in 2000 housed about 8 percent of the national population on about 0.2 percent of the land area of the contiguous 48 states. Moreover, New York stands at the center of the urbanized northeastern seaboard, which contained about 60 million people in the late 1990s. 。
New York has been among the most ethnically diverse cities in the world since the 1640s, when fewer than 1,000 total residents spoke more than 15 languages. Between 1880 and 1919, more than 23 million Europeans immigrated to the United States. At least 17 million of them disembarked in New York. No one knows how many remained there, but as early as 1880, more than half the city’s working population was foreign-born, providing New York with the largest immigrant labor force on earth. 。
Half a century later, the city still contained 2 million foreign-born residents (including 517,000 Russians and 430,000 Italians) and an even larger number of persons of foreign parentage. And at the end of the 20th century, the pattern remained the same. In 1996 the U.S. Census Bureau reported that more than 11 out of every 20 New Yorkers were immigrants or the children of immigrants. Nearly half of all Bronx residents and one-third of Manhattan’s were Hispanic and nearly one-fifth of the population of Queens was Asian-American. Researchers estimated that immigrants would make up about 33 percent of the city’s population in 2000, approaching the 20th-century peak of about 40 percent, reached in 1910. 。
Meanwhile, the black proportion of the New York population, which reached 20 percent in the colonial period and declined to less than 2 percent in the 1870s, began a slow rise thereafter. According to the 2000 census, whites make up 44.7 percent of the city’s population; blacks, 26.6 percent; Asians, 9.8 percent; Native Americans, 0.5 percent; Native Hawaiians and other Pacific Islanders, 0.1 percent; and people of mixed heritage or not reporting race, 18.3 percent. Hispanics, who may be of any race, are 27 percent of the population. By the late 1990s, more than 120 languages were spoken in the city’s schools, and there were dozens of ethnic churches, political organizations, cultural festivals, and parades, as well as scores of foreign-language newspapers, magazines, and television and radio stations. Although rivalries among the various groups could be intense, the very diversity of the city permitted immigrants to mingle more easily than in most other parts of the nation. 。
IV
Culture and Education 。
Because of its huge size, its concentrated wealth, and its mixture of people from around the world, New York City offers its residents and visitors a staggering array of cultural riches and educational opportunities. The city is the world’s leading center for performing arts and its museums contain a wide range of artistic and historical subjects. A mixture of cultures from around the world is reflected in the street festivals and ethnic celebrations that take place year-round. In addition, more than 100 institutions of higher education operate in New York City, including some of the nation’s more prestigious centers of learning. 。
http://encarta.msn.com/encyclopedia_761576416/New_York_(city).html。
抱起亚轩找小葵
英语介绍比利时经济
水星最接近太阳，是太阳系中第二小行星。水星在直径上小于木卫三和土卫六，但它更重。公转轨道: 距太阳 57,910,000 千米 (0.38 天文单位)行星直径: 4,880 千米 质量: 3.30e23 千克在古罗马神话中水星是商业、旅行和偷窃之神，即古希腊神话中的赫耳墨斯，为众神传信的神，或许由于水星在空中移动得快，才使它得到这个名字。 早在公元前3000年的苏美尔时代，人们便发现了水星，古希腊人赋于它两个名字：当它初现于清晨时称为阿波罗，当它闪烁于夜空时称为赫耳墨斯。不过，古希腊天文学家们知道这两个名字实际上指的是同一颗星星，赫拉克赖脱（公元前5世纪之希腊哲学家）甚至认为水星与金星并非环绕地球，而是环绕着太阳在运行 。
金星是离太阳第二近，太阳系中第六大行星。在所有行星中，金星的轨道最接近圆，偏差不到1％.轨道半径:距太阳 108,200,000 千米 (0.72 天文单位)行星直径:12,103.6 千米质量:4.869e24 千克 金星 (希腊语: 阿佛洛狄特；巴比伦语: Ishtar)是美和爱的女神，之所以会如此命名，也许是对古代人来说，它是已知行星中最亮的一颗。（也有一些异议，认为金星的命名是因为金星的表面如同女性的外貌。）金星在史前就已被人所知晓。除了太阳与月亮外，它是最亮的一颗。就像水星，它通常被认为是两个独立的星构成的：晨星叫Eosphorus，晚星叫Hesperus，希腊天文学家更了解这一点。
地球是距太阳第三颗，也是第五大行星：轨道半径:149,600,000 千米 (离太阳1.00 天文单位)行星直径:12,756.3 千米质量:5.9736e24 千克 >地球是唯一一个不是从希腊或罗马神马中得到的名字。Earth一词来自于古英语及日耳曼语。这里当然有许多其他语言的命名。在罗马神话中，地球女神叫Tellus－肥沃的土地（希腊语：Gaia, 大地母亲）
月球是地球唯一一颗天然卫星：轨道半径.距地球384,400千米行星直径：3476千米质量：7.35e22千克 古罗马人称之为Luna，古希腊人称之为Selene或阿尔特弥斯（月亮与狩猎的女神），另外在其他神话中它还有许多名字。 理所当然，月球早在史前就已被人所知道。它是空中仅次于太阳的第二亮物体。由于月球每月绕地球公转一周，地球、月球、太阳之间的角度不断变化；我们把它叫做一个朔望月。一个连续新月的出现需要29.5天（709小时），随月球轨道周期（由恒星测量）因地球同时绕太阳公转变化而变化。
火星为距太阳第四远，也是太阳系中第七大行星： 公转轨道:离太阳227,940,000 千米 (1.52 天文单位) 行星直径:6,794 千米 质量:6.4219e23 千克火星(希腊语: 阿瑞斯)被称为战神。这或许是由于它鲜红的颜色而得来的；火星有时被称为“红色行生”。（趣记：在希腊人之前，古罗马人曾把火星人微言轻农耕之神来供奉。而好侵略扩张的希腊人却把火星作为战争的象征）而月份三份的名字也是得自于火星。
Phobos (英语发音"FOH bus")是火星的两颗卫星中较大，也是离火星较近的一颗。火卫一与火星之间的距离也是太阳系中所有的卫星与其主星的距离中最短的，从火星表面算起，只有6000千米。它也是太阳系中最小的卫星之一。公转轨道:距火星中心9378 千米 卫星直径:22.2 千米 (27 x 21.6 x 18.8) 质量:1.08e16 千克在希腊神话中，火卫一是阿瑞斯（火星）和阿芙罗狄蒂（金星）的一个儿子。“phobos”在希腊语中意味着“恐惧”（是“phobia”－恐惧的构词成分）。火卫一在1877年由Hall发现，1971年由“水手9号”首次拍得照片，并由1977年的“海盗1号”、1988年的“火卫一号”进行观测。
木星是离太阳第五颗行星，而且是最大的一颗，比所有其他的行星的合质量大2倍（地球的318倍）。
公转轨道:距太阳 778,330,000 千米 (5.20 天文单位)行星直径:142,984 千米 (赤道)质量:1.900e27 千克木星(a.k.a. Jove; 希腊人称之为 宙斯)是上帝之王，奥林匹斯山的统治者和罗马国的保护人，它是Cronus（土星）的儿子。木星是天空中第四亮的物体（次于太阳，月球和金星；有时候火星更亮一些），早在史前木星就已被人类所知晓。根据伽利略1610年对木星四颗卫星：木卫一，木卫二，木卫三和木卫四（现常被称作伽利略卫星）的观察，它们是不以地球为中心运转的第一个发现，也是赞同哥白尼的日心说的有关行星运动的主要依据；由于伽利略直言不讳地支持哥白尼的理论而被宗教裁判所逮捕，并被强迫放弃自己的信仰，关在监狱中度过了余生。
木星的卫星
木星有16颗已知卫星，4颗大伽利略发现的卫星，12颗小的。
由于伽利略卫星产生的引潮力，木星运动正逐渐地变缓。同样，相同的引潮力也改变了卫星的轨道，使它们慢慢地逐渐远离木星。
木卫一，木卫二，木卫三由引潮力影响而使公转共动关系固定为1:2:4，并共同变化。木卫四也是这其中一个部分。在未来的数亿年里，木卫四也将被锁定，以木卫三的两倍公转周期，木卫一的八倍来运行。
木星的卫星由宙斯一生中所接触过的人来命名（大多是他的情人）。
卫星 距离
（千米） 半径
（千米） 质量
（千克） 发现者 发现日期
木卫十六 128000 20 9.56e16 Synnott 1979 。
木卫十五 129000 10 1.91e16 Jewitt 1979 。
木卫五 181000 98 7.17e18 Barnard 1892 。
木卫十四 222000 50 7.77e17 Synnott 1979 。
木卫一 422000 1815 8.94e22 伽利略 1610 。
木卫二 671000 1569 4.80e22 伽利略 1610 。
木卫三 1070000 2631 1.48e23 伽利略 1610 。
木卫四 1883000 2400 1.08e23 伽利略 1610 。
木卫十三 11094000 8 5.68e15 Kowal 1974 。
木卫六 11480000 93 9.56e18 Perrine 1904 。
木卫十 11720000 18 7.77e16 Nicholson 1938 。
木卫七 11737000 38 7.77e17 Perrine 1905 。
木卫十二 21200000 15 3.82e16 Nicholson 1951 。
木卫十一 22600000 20 9.56e16 Nicholson 1938 。
木卫八 23500000 25 1.91e17 Melotte 1908 。
木卫九 23700000 18 7.77e16 Nicholson 1914 。
较小卫星的数值是约值。
木星的光环
光环 距离
（千米） 宽度
（千米） 质量
（千克）
Halo 100000 22800 ? 。
Main 122800 6400 1e13 。
Gossamer 129200 850000 ? 。
（距离是指从木星中心到光环内侧边缘 。
土星是离太阳第六远的行星，也是九大行星中第二大的行星：
公转轨道: 距太阳 1,429,400,000 千米 (9.54 天文单位) 。
卫星直径: 120,536 千米 (赤道) 。
质量: 5.68e26 千克 。
在罗马神话中，土星（Saturn）是农神的名称。希腊神话中的农神Cronus是Uranus（天王星）和该亚的儿子，也是宙斯（木星）的父亲。土星也是英语中“星期六”（Saturday）的词根。( 。
土星在史前就被发现了。伽利略在1610年第一次通过望远镜观察到它，并记录下它的奇怪运行轨迹，但也被它给搞糊涂了。早期对于土星的观察十分复杂，这是由于当土星在它的轨道上时每过几年，地球就要穿过土星光环所在的平面。（低分辨率的土星图片所以经常有彻底性的变化。）直到1659年惠更斯正确地推断出光环的几何形状。在1977年以前，土星的光环一直被认为是太阳系中唯一存在的；但在1977年，在天王星周围发现了暗淡的光环，在这以后不久木星和海王星周围也发现了光环 。
天王星是太阳系中离太阳第七远行星，从直径来看，是太阳系中第三大行星。天王星的体积比海王星大，质量却比其小。
公转轨道: 距太阳2,870,990,000 千米 (19.218 天文单位) 。
行星直径: 51,118 千米（赤道）
质量: 8.683e25 千克 。
读天王星的英文名字，发音时要小心，否则可能会使人陷于窘迫的境地。Uranus应读成"YOOR a nus" ，不要读成"your anus"（你的肛门）或是"urine us"（对着我们撒尿）。
乌拉诺斯是古希腊神话中的宇宙之神，是最早的至高无上的神。他是该亚的儿子兼配偶，是Cronus（农神土星）、独眼巨人和泰坦（奥林匹斯山神的前辈）的父亲。
天王星是由威廉·赫歇耳通过望远镜系统地搜寻，在1781年3月13日发现的，它是现代发现的第一颗行星。事实上，它曾经被观测到许多次，只不过当时被误认为是另一颗恒星（早在1690年John Flamsteed便已观测到它的存在，但当时却把它编为34 Tauri）。赫歇耳把它命名为"the Georgium Sidus（天竺葵）"（乔治亚行星）来纪念他的资助者，那个对美国人而言臭名昭著的英国国王：乔治三世；其他人却称天王星为“赫歇耳”。由于其他行星的名字都取自希腊神话，因此为保持一致，由波德首先提出把它称为“乌拉诺斯(Uranus)”（天王星），但直到1850年才开始广泛使用。
天王星的卫星
天王星有15颗已命名的卫星，以及2颗已发现但暂未命名的卫星。
与太阳系中的其他天体不同，天王星的卫星并不是以古代神话中的人物而命名的，而是用莎士比亚和罗马教皇的作品中人物的名字。
它们自然分成两组：由旅行者2号发现的靠近天王星的很暗的10颗小卫星和5颗在外层的大卫星。（右图）
它们都有一个圆形轨道围绕着天王星的赤道（因此相对于赤道面有一个较大的角度）。
卫星 距离
（千米） 半径
（千米） 质量
（千克） 发现者 发现日期
天卫六 50000 13 ? 旅行者2号 1986 。
天卫七 54000 16 ? 旅行者2号 1986 。
天卫八 59000 22 ? 旅行者2号 1986 。
天卫九 62000 33 ? 旅行者2号 1986 。
天卫十 63000 29 ? 旅行者2号 1986 。
天卫十一 64000 42 ? 旅行者2号 1986 。
天卫十二 66000 55 ? 旅行者2号 1986 。
天卫十三 70000 27 ? 旅行者2号 1986 。
天卫十四 75000 34 ? 旅行者2号 1986 。
天卫十八 75000 20 ? Karkoschka 1999 。
天卫十五 86000 77 ? 旅行者2号 1985 。
天卫五 130000 236 6.30e19 Kuiper 1948 。
天卫一 191000 579 1.27e21 Lassell 1851 。
天卫二 266000 585 1.27e21 Lassell 1851 。
天卫三 436000 789 3.49e21 赫歇耳 1787 。
天卫四 583000 761 3.03e21 赫歇耳 1787 。
天卫十六 7200000 30 ? Gladman 1997 。
天卫十七
12200000 60 ? Gladman 。
1997
天王星的光环
光环 距离
（千米） 宽度
（千米）
1986U2R 38000 2,500 。
6 41840 1-3
5 42230 2-3
4 42580 2-3
Alpha 44720 7-12 。
Beta 45670 7-12 。
Eta 47190 0-2
Gamma 47630 1-4 。
Delta 48290 3-9 。
1986U1R 50020 1-2 。
Epsilon 51140 20-100 。
（距离是指从天王星的中心算到光环的内边的长度 。
海王星是环绕太阳运行的第八颗行星，也是太阳系中第四大天体（直径上）。海王星在直径上小于天王星，但质量比它大。
公转轨道: 距太阳 4,504,000,000 千米 (30.06 天文单位) 。
行星直径: 49,532 千米（赤道）
质量: 1.0247e26 千克 。
在古罗马神话中海王星（古希腊神话：波塞冬(Poseidon)）代表海神。
在天王星被发现后，人们注意到它的轨道与根据牛顿理论所推知的并不一致。因此科学家们预测存在着另一颗遥远的行星从而影响了天王星的轨道。Galle和d\'Arrest在1846年9月23日首次观察到海王星，它出现的地点非常靠近于亚当斯和勒威耶根据所观察到的木星、土星和天王星的位置经过计算独立预测出的地点。一场关于谁先发现海王星和谁享有对此命名的权利的国际性争论产生于英国与法国之间（然而，亚当斯和勒威耶个人之间并未有明显的争论）；现在将海王星的发现共同归功于他们两人。后来的观察显示亚当斯和勒威耶计算出的轨道与海王星真实的轨道偏差相当大。如果对海王星的搜寻早几年或晚几年进行的话，人们将无法在他们预测的位置或其附近找到它。
仅有一艘宇宙飞船旅行者2号于1989年8月25日造访过海王星。几首我们所知的全部关于海王星的信息来自这次短暂的会面。
海王星的卫星
海王星有8颗已知卫星：7颗小卫星和海卫一。
卫星 距离
（千米）
半径
（千米）
质量
（千克）
发现者 发现日期
海卫三 48000 29 ? 旅行者2号 1989 。
海卫四 50000 40 ? 旅行者2号 1989 。
海卫五 53000 74 ? 旅行者2号 1989 。
海卫六 62000 79 ? 旅行者2号 1989 。
海卫七 74000 96 ? 旅行者2号 1989 。
海卫八 118000 209 ? 旅行者2号 1989 。
海卫一 355000 1350 2.14e22 Lassell 1846 。
海卫二 5509000 170 ? Kuiper 1949 。
海王星的光环
光环 距离
（千米） 宽度
（千米） 另称
Diffuse 41900 15 1989N3R, Galle 。
Inner 53200 15 1989N2R, 勒威耶 。
Plateau 53200 5800 1989N4R, Lassell, Arago 。
Main 62930 < 50 1989N1R, Adams 。
（距离是海王星中心到光环的内端）
一般认为，冥王星是离太阳最远而且是最小的行星。太阳系中有七颗卫比冥王星大（月球, 木卫一, 木卫二, 木卫三, 木卫四, 土卫六 and 海卫一）。
公转轨道: 离太阳平均距离5,913,520,000 千米 (39.5 天文单位) 。
行星直径: 2274 千米
质量: 1.27e22 千克 。
罗马神话中，冥王星（希腊人称之为Hades哈迪斯）是冥界的首领。这颗行星得到这个名字（而不采纳其他的建议）可能是由于他离太阳太远以致于一直沉默在无尽的黑暗之中，也可能是因为冥王星(pluto)开头的两字母是Percival Lowell是缩写。
冥王星是在1930年由于一个幸运的巧合而被发现的。一个后来被发现错误的计算“断言”基于天王星与海王星的运行研究，在海王星后还有一颗行星。美国亚利桑那州的Lowell天文台的Clyde W. Tombaugh由于不知道这个计算错误，对太阳系进行了一次非常仔细的观察，然而正因为这样，发现了冥王星。
Charon ( "KAIR en" )是冥王星唯一一颗已知的卫星：
公转轨道: 离冥王星19,640 千米 。
卫星直径: 1172 千米
质量: 1.90e21 千克 。
Charon（卡戎或查农－－译注）是以神话中的人物命名的，他专门摆渡死者通过River Styx冥河来到冥界。
（虽然学术界以这个神秘人物来命名，但冥卫一的发现者这样命名也是为了纪念他的妻子Charlene。正如所知道的，他们英语发音的第一音节是相同的，就象“shard"（"SHAHR en"）一样。）
大圣杰锅是
吐血规求求英语短文若干,数学题若干
http://en.wikipedia.org/wiki/Economy_of_Belgium。
http://www.diplomatie.be/EN/belgium/belgiumdetail.asp?TEXTID=49019。
Belgian economy 。
Open and competitive。
With a surface area of 30,500 km² and a population of 10,446,000, Belgium is one of the smallest Member States in the European Union. However, it has a GDP of EUR 288.09 billion (in 2004) and is one of the ten largest trading nations in the world. It primarily owes its comparably large economic might to its central location and the high productivity of its work force.。
A central location and good infrastructure。
Belgium has one major advantage: its central location. In the past, this was often a handicap since the great European powers repeatedly came here to battle out their differences. However, in times of peace and open borders, the battlefield of Europe was also the place where trade and industry was able to flourish.。
So, Belgium did not just bear witness to the clash of arms and human suffering at Waterloo, Passendale and Bastogne, but was also home to the commercial glory of Brugges and Antwerp and the remarkable worldwide expansion of businesses from the Walloon industrial basins.。
Nature saw to it that at the end of the 14th century the course of the Schelde had evolved in such a way that by the 16th century a modest port could develop into the most important trade centre to the north of the Alps. Antwerp is the furthest inland port in north west Europe and has the most active economic zone in Europe as its hinterland. Today, at the beginning of the 21st century, it is the fourth largest port in the world and the fastest growing port for container transport out of the entire Hamburg-Le Havre range. In addition to the sea ports of Antwerp, Zeebrugge and Ghent and the large European motorways, railways and waterways, Belgium developed an efficient transport network on its territory allowing it to take full advantage of its central location. As a result, Belgium was able to expand to become a distribution capital and a European bridge for business throughout the whole world.。
Sensible infrastructure。
Belgium has always invested a great deal in its transport infrastructure. It was the first country in Europe where trains were used and it quickly built up the densest railway network in the world. Transport on the waterways was optimalised by constructing inventive boat lifts such as those on the Canal du Centre which has since been recognised by UNESCO as a World Heritage Site. Over the years, the port of Antwerp acquired large dock yards and locks and currently has the largest lock in the world, the Berendrecht lock.。
Belgium is focusing its efforts in a bid to let transport run quickly and continuously further through the country. It has modern airports and quick connections with the high-speed train. As regards goods transport, the country wants to make full use of the advantages offered by combined transport. A number of container ports for inland shipping have recently been built and the port of Antwerp was expanded once again with a tidal container dock - the Deurganck dock - which allows ships to be dealt with even more quickly. The rail infrastructure in the port area and the connections to the port are been extended further.。
Economic change。
Belgium initially owed a major part of its industrialisation and fast economic growth to the minerals present in the ground in the south of the country. The impetus for the country's strong industrial development had already been provided before independence. So, as early as during the era of the United Kingdom of the Netherlands (1815-1830), when the countries currently known as Belgium and the Netherlands together formed one single country, the Société générale was established, which gradually developed into a powerful holding company that controlled a large part of the Belgian economy.。
The centre moves from Wallonia to Flanders。
Coal mining and heavy industry, which enabled Belgium to become the most industrialised country in Europe after Great Britain, lost their dominant status in the second half of the 20th century. The coal was located deep underground and mining was too expensive in the face of foreign competition. In the middle of the 20th century, Belgium still had 100,000 miners, in 1983 the last Walloon mine closed and 1992 marked the end of the last mine in Limburg. The steel industry also declined sharply during the same period as a result of the European Coal and Steel Community and the associated redevelopment of Europe's steel sector. In Wallonia, which was the base of Belgium's industrial development, large areas are still struggling with economic restructuring. The Walloon government recently launched a large-scale 'Marshall plan' to boost the region's economy.。
While all this was taking place, Flanders was moving up in the world. It owed this mainly to its favourable location and the port of Antwerp. The supply of oil and the investments from large foreign companies led to the expansion of the largest concentration of petrochemical activity in the world, after Houston.。
American companies also played an important role. After the war they started looking for cheaper product options and after the launch of the European Economic Community, they wanted to take advantage of the additional predicted growth. In Flanders, they found reliable workers who were considerably cheaper than the Walloons.。
Flanders was therefore able to catch up with Wallonia in industrial terms. Flanders' GDP, which only represented 44% of Belgian GDP in 1995, rose to 55% after the Golden Sixties.。
From industry to services。
During this period, Belgium, like other industrialised countries, made a large shift towards the tertiary sector. Currently, almost 75% of the workforce is employed in the services sector and just under 25% is employed in industry. Agriculture represents approximately 1%.。
The fact that industry's share in the economy has declined (to approximately 20% of the value added) does not automatically mean that deindustrialisation will continue. In the last 10 years, industrial production has increased in volume almost as quickly as the Belgian economy as a whole. The decline in the share of industry in GDP can be attributed to higher productivity which has led prices to fall. Industry still accounts for 80% of Belgian exports.。
Belgian agriculture has developed into a highly competitive sector with one of the highest rates of productivity in Europe. In Flanders, the companies are on average 16.2 ha and mainly concentrate on pig farming and market gardening. In Wallonia, the companies are on average 38.2 ha and agriculture is more extensive. The focus here is on beef and dairy cattle and arable farming.。
The perfect 'open economy'。
A densely populated but small country which is centrally located in one of the most economically active regions in the world has to have an open economy. In the early Middle Ages, products from what can now be referred to as 'Belgian soil' were already being sold throughout what was then considered to be the whole world. Bruges, followed by Antwerp were places where traders and products from all over the world came together. It was Bruges that gave the world the 'stock market' and in the 16th century, Antwerp started new financial techniques and loaned its capital the world's major powers. At the end of the 19th and beginning of the 20th century, Belgian industrialists, equipped with their machines, railways and large infrastructures, played an important role in developing and opening up large and small countries across the globe.。
The age-old openness of the Belgian economy has increased in recent decades. As a result of the significant proportion of international trade in GDP and the substantial income from foreign investment, the country has been called 'the perfect example of an open economy'.。
The average value of export and import of goods as a percentage of GDP equates to almost 83%, which is the highest percentage out of all the 25 countries in the European Union. Belgium also holds first place for the percentage of GDP accounted for by foreign direct investment.。
Belgium: the largest exporter。
Belgium, which accounts for less than 0,2% of the world population and has a market share of 3,4% of exports and 3% of imports, is ranked tenth for international trade in goods. As regards international trade in services, Belgium has a market share of 3,6% and is ranked eighth.。
Approximately 20% of Belgians exports is comprised of consumer goods. Intermediate goods account for about 60%. These are mainly machines and equipment, accounting for over 28% of exports, and chemical and allied products accounting for almost 22%.。
It can also be seen from export figures that Belgium is a country which assembles cars. Approximately 95% of the 900,000 cars manufactured by Volvo, Opel, Volkswagen and Ford in Belgium are exported. They account for almost 15% of Belgian exports. Plastics account for over 3%, pharmaceutical products and organic chemical products represent about 5% each. Metals (iron and steel, non ferrous metals and processed metal products) make up over 4% and food stuffs constitute almost 9%.。
Belgium is the world's largest exporter of diamonds and carpets and is the second largest exporter of plant fibres, chocolate and margarine. It is the world number three for glass exports and ranks fourth for the export of eggs, non alcoholic drinks and cars.。
Belgium is the world leader in terms of export per capita and can justifiably call itself the 'world's largest exporter'.。
The European dimension。
Belgium's position in the international economy and the fact that the country is able to make such good use of its economic advantages is in large part thanks to the position it occupies in the unified European market.。
Export to its 'natural partners' and the other EU countries (15 Member States) accounts for approximately 75% of Belgium's total exports. Out of this 75%, 65% goes to the euro zone and 11% to the other EU countries. The European countries outside EU-15 account for 7%. (The 10 new EU Member States accounted for almost 3% of export in 2003 i.e. before their accession). Asia represents over 9% and the US about 5%. The importance of the European dimension is clear from the fact that half of the goods that are processed in the port of Antwerp come from or are destined for other European countries.。
There is also the economic effect of the presence of the European and other international organisations. The European organisations account, directly and indirectly, for almost one tenth of the jobs in the Brussels Capital Region. The international organisations and their employees inject a large amount of money into the Belgian economy through their spending. Belgium does therefore not need to be convinced of the benefit of European integration and is eagerly helping to pave the way forward. In the past, Belgian politicians have often played a key role in mapping out the path for European construction and in redefining common policy. As an exporting country, Belgium was also a major partisan of the introduction of the common European currency - the euro. The National Bank of Belgium forms part of the European System of Central Banks and, as such, is involved in defining and implementing monetary policy in the euro zone.。
Of course, the liberalisation of the European market did not just provide greater potential for Belgian products, but also increased the likelihood of fierce competition. Belgium has maintained its position and managed to remain competitive, mainly by boosting the productivity of its companies and workers. In Belgian industry, a worker currently produces on average twice as much as a worker in 1980.。
The Belgian worker: an important asset。
The high productivity of Belgian workers plays a vital role in the good performance of the Belgian economy.。
Belgian labour productivity is amongst the highest in the world. Only the US (and the exceptional case of Luxembourg) are ahead of Belgium in the most relevant category (GDP per worker). Belgium is ranked third for productivity per hour worked. In fact, Belgium always features amongst the best regardless of the way in which the quality of workers is measured. Labour productivity is particularly high in industry, construction and finance. Belgian workers also have the lowest rate of absenteeism in the EU.。
One of the most important factors after the high level of productivity is the high quality of the Belgian education system which can be seen from international comparative studies, such as the PISA study conducted by the OECD. Approximately one third of people aged between 18 and 24 are in higher education, which is the highest figure in the EU. Two Belgian universities feature in the list of the top 10 best universities in the world (outside the US) compiled by American scientists.。
A special kind of SME country。
In structural terms, the Belgian business world consists of a series of large companies and a very high number of SMEs. Some Belgian companies employ thousands of people worldwide and the Stella Artois Brewery in Leuven was able to expand into Inbev, the largest brewery group in the world. However, the majority of the large companies belong to foreign groups. Recently, foreign shareholders took over the control of some important Belgian companies and currently, the decision-making centres for two thirds of the top 100 Belgian companies are located abroad.。
In addition, the Belgian economy is supported by small and medium-sized enterprises. Approximately 83% of Belgian companies have less than 10 employees and 97% of the companies employ less than 50 people. SMEs account for over 70% of GDP. The majority of Belgian SMEs are family businesses but this does not prevent them from being important players on the international market. Belgian SMEs have turned out to be particularly good niche companies which are often market leaders in their own sectors.。
It can be seen from European comparisons how special these small companies are: Belgian SMEs are the most profitable in the EU. Belgium is also the only European country where the profitability of SMEs is considerably higher than that of large companies.。
A genuine collective bargaining economy。
The Belgians are not partial to harsh confrontation. This is demonstrated in the way that relationships are organised within the economy. Belgium is a genuine collective bargaining economy in which a great deal is regulated by agreements between worker and employer representative organisations. The government acts as mediator. Social dialogue takes place at company, sectoral and national level. In negotiations on collective labour agreements, wage increases are restricted by the Law on Safeguarding Competitiveness (De wet op het concurrentievermogen/La loi de sauvegarde de la competitivité). The law has the task of ensuring that the competitive position of Belgian companies does not suffer in relation to companies in the neighbouring countries.。
Belgian companies are brought together in a number of bodies which reflect regional and sectoral divisions. At national level there is the Federation of Enterprises in Belgium (FEB/VBO) and at regional level there is the association of Flemish Companies i.e. the Flemish Economic Union (VOKA), the Union of Walloon Enterprises (UWE) and the Union of Enterprises in Brussels (UEB/VOB).。
The level of union membership in Belgium is 60% which is the highest level after the Scandinavian countries. The unions do not just play a key role in social dialogue but are also responsible for other areas such as the payment of unemployment compensation. There are three major unions: the socialist General Labour Federation of Belgium, the Confederation of Christian Trade Unions and the Federation of Liberal Trade Unions.。
The role of the government。
As is the case in many European countries, the government plays a relatively large role in the national economy. It ensures that income is redistributed by managing and co-financing the social security system to which the Belgians are very attached. It is regarded as one of the most efficient systems in the world: Belgium has one of the lowest poverty levels.。
The role that the government plays in social dialogue is also very important. If employer and worker representative organisations cannot reach an agreement, the government acts as a mediator and, if necessary, takes the plunge. Moreover, it is well aware of the importance of the international context in which Belgian companies are active and the importance of safeguarding competitiveness.。
Economic powers of the Regions。
Over the last 25 years, Belgium has evolved into a Federal state with a large degree of autonomy for the three Regions (Flanders, Brussels and Wallonia). This has also had consequences for economic powers. The Regions are responsible for the agricultural, energy, employment and economic policies (economic expansion, innovation policy, restructuring policy), foreign trade, public works and public transport. The Federal government is responsible for social security (unemployment, sickness and invalidity, pensions, child benefit) and also has the necessary powers to ensure that the country retains its economic and monetary unity.。
Public finances。
As regards public finances, Belgium is still suffering the consequences of the anti-cyclical policy pursued by the government in the 1970s. The interest on the debt built up as a result of deficit spending has left the country with a very high level of debt. It continued however to benefit from the trust of the capital markets, primarily since Belgian debt was virtually solely financed by Belgians themselves. Traditionally, they have one of the highest savings rates in the world.。
An austere policy and good debt management have since enabled the Belgian government to reorganise its finances. The Maastricht indicators governing inclusion into the European currency union acted as an extra incentive in this respect. The level of debt, which totalled 137.1% of GDP in 1993, has since decreased to 95.8%. The budget has been balanced since 2000 which currently makes Belgium one of the best performing countries within the EU.。
The budget surpluses which are planned from 2007 onwards will be put aside in the Silver Fund which will help to cover the financial consequences of the aging of the population. The level of debt will have been reduced to approximately 79% by 2009.。
Looking to the future...。
Belgium is aware of the strengths and weaknesses of its economy. It wants to continue to keep its favourable position in the future. Research and development are, of course, of vital importance and Belgium scores highly is this area too.。
As regards investment in innovation and research as a percentage of GDP, Belgium scores better than the EU average. It comes sixth after Sweden, Finland, Germany, Denmark and France. An important aspect is that the contribution made by companies in this area is so high. They account for 64% of the investments in research and development which - after Sweden, Finland and Germany - represents the highest percentage in the EU.。
Belgium has more inhabitants that are active in the area of research and development that the European average and they are more productive that their colleagues in other countries: Belgium has 929 scientific publications per million inhabitants on average per year, compared to 550 in Japan and 775 in the US. Another important factor is the continued growth of the ICT sector. The proportion accounted for by the ICT sector in the Belgian economy rose from 3.35% in 1995 to 4.27% in 2004. During this period, the sector accounted for 19.5% of the increase in GDP and currently provides 20% of total R&D efforts. 。
字数超限了。。
小韩在追星
经典英语范文
With best wishes for a happy birthday.。
Each birthday is a milestone we touch along life's way.。
May every special happiness fill this day for you and may the year bring everything you look forward to.。
Happy birthday, on this year special day, may gladness fill your every hour with joy to light your way.。
May your memories today be warm ones. May your dreams today be dear. May your joy last through the year. Have a wonderful birthday!。
May your life be brighter as each birthday comes and goes, with new happiness unfolding（绽开） like the petal（花瓣） of a rose. have a wonderful birthday!。
The golden key to happiness, to health and fortune, too. This greeting symbolizes（象征） all three of these for you.。
Sunny, bright, delightful, warm and wonderful, too--- That's the kind of birthday this wish is wishing you!。
Whatever dream you're dreaming, may each one of them come true; whatever plans you're making may they all work out for you. Happy birthday!。
Love is always my fight to you. Happy birthday!。
Roses, sweet and fragrant, sent to you to say, may each hour be a happy one on this special day. Have a happy birthday!。
To love is nothing. To be loved is something. to love, and be loved, is everything. 。
May you have many, many happy birthday and always keep loveliness and charm.。
Wish you all happiness, health and prosperity（事业发达） with many many returns of the day.。
Please accept my gift for your birthday, not for its own value, but for the sake of the thoughts it represents.。
A man is not old as long as he is seeking something.。
Oil Refining
An important new industry, oil refining, grew after the Civil war. Crude oil, or petroleum - a dark, thick ooze from the earth - had been known for hundreds of years, but little use had ever been made of it. In the 1850's Samuel M. Kier, a manufacturer in western Pennsylvania, began collecting the oil from local seepages and refining it into kerosene. Refining, like smelting, is a process of removing impurities from a raw material.。
Kerosene was used to light lamps. It was a cheap substitute for whale oil, which was becoming harder to get. Soon there was a large demand for kerosene. People began to search for new supplies of petroleum.。
The first oil well was drilled by E.L. Drake, a retired railroad conductor. In 1859 he began drilling in Titusville, Pennsylvania. The whole venture seemed so impractical and foolish that onlookers called it " Drake's Folly". But when he had drilled down about 70 feet(21 meters), Drake struck oil. His well began to yield 20 barrels of crude oil a day.。
News of Drake's success brought oil prospectors to the scene. By the early 1860's these wildcatters were drilling for " black gold" all over western Pennsylvania. The boom rivaled the California gold rush of 1848 in its excitement and Wild West atmosphere. And it brought far more wealth to the prospectors than any gold rush.。
Crude oil could be refined into many products. For some years kerosene continued to be the principal one. It was sold in grocery stores and door-to-door. In the 1880's refiners learned how to make other petroleum products such as waxes and lubricating oils. Petroleum was not then used to make gasoline or heating oil。
The Salinity of Ocean Waters。
If the salinity of ocean waters is analyzed, it is found to vary only slightly from place to place. Nevertheless, some of these small changes are important. There are three basic processes that cause a change in oceanic salinity. One of these is the subtraction of water from the ocean by means of evaporation--- conversion of liquid water to water vapor. In this manner the salinity is increased, since the salts stay behind. If this is carried to the extreme, of course, white crystals of salt would be left behind.。
The opposite of evaporation is precipitation, such as rain, by which water is added to the ocean. Here the ocean is being diluted so that the salinity is decreased. This may occur in areas of high rainfall or in coastal regions where rivers flow into the ocean. Thus salinity may be increased by the subtraction of water by evaporation, or decreased by the addition of fresh water by precipitation or runoff.。
Normally, in tropical regions where the sun is very strong, the ocean salinity is somewhat higher than it is in other parts of the world where there is not as much evaporation. Similarly, in coastal regions where rivers dilute the sea, salinity is somewhat lower than in other oceanic areas.。
A third process by which salinity may be altered is associated with the formation and melting of sea ice. When sea water is frozen, the dissolved materials are left behind. In this manner, sea water directly materials are left behind. In this manner, sea water directly beneath freshly formed sea ice has a higher salinity than it did before the ice appeared. Of course, when this ice melts, it will tend to decrease the salinity of the surrounding water.。
In the Weddell Sea Antarctica, the densest water in the oceans is formed as a result of this freezing process, which increases the salinity of cold water. This heavy water sinks and is found in the deeper portions of the oceans of the world.。
NOTE：
salinity / sэ'linэti; sэ`linэti/ 。
n [U] the high salinity of sea water 海水的高含盐量.。
--->>>saline / 'seilain; US -li:n; `selin/ 。
1.adj [attrib 作定语] (fml 文) containing salt; salty 含盐的; 咸的: 。
* a saline lake 盐湖 * saline springs 盐泉 。
* saline solution, eg as used for gargling, storing contact lenses, etc 盐溶液（如用于漱喉、存放隐形眼镜等）.。
2. n [U] (medical 医) solution of salt and water 盐水.。
在三角形abc中，ad是中线，ae是高，求证ab^2-ac^2=2bc*de。
有一艘船，你第一个登船，8岁的同学第二个登船，9岁同学第三个登船，10岁的同学第四个登船，以此类推。请问第一个登船的同学几岁。
小韩在追星
有关Iceland的英文资料 要中文翻译
31 British Columbia。
British Columbia is the third largest Canadian provinces, both in area and population. It is nearly 1.5 times as large as Texas, and extends 800 miles(1,280km) north from the United States border. It includes Canada’s entire west coast and the islands just off the coast. 。
Most of British Columbia is mountainous, with long rugged ranges running north and south. Even the coastal islands are the remains of a mountain range that existed thousands of years ago. During the last Ice Age, this range was scoured by glaciers until most of it was beneath the sea. Its peaks now show as islands scattered along the coast.。
The southwestern coastal region has a humid mild marine climate. Sea winds that blow inland from the west are warmed by a current of warm water that flows through the Pacific Ocean. As a result, winter temperatures average above freezing and summers are mild. These warm western winds also carry moisture from the ocean.。
Inland from the coast, the winds from the Pacific meet the mountain barriers of the coastal ranges and the Rocky Mountains. As they rise to cross the mountains, the winds are cooled, and their moisture begins to fall as rain. On some of the western slopes almost 200 inches (500cm) of rain fall each year.。
More than half of British Columbia is heavily forested. On mountain slopes that receive plentiful rainfall, huge Douglas firs rise in towering columns. These forest giants often grow to be as much as 300 feet(90m) tall, with diameters up to 10 feet(3m). More lumber is produced from these trees than from any other kind of tree in North America. Hemlock, red cedar, and balsam fir are among the other trees found in British Columbia.。
32 Botany
Botany, the study of plants, occupies a peculiar position in the history of human knowledge. For many thousands of years it was the one field of awareness about which humans had anything more than the vaguest of insights. It is impossible to know today just what our Stone Age ancestors knew about plants, but form what we can observe of pre-industrial societies that still exist a detailed learning of plants and their properties must be extremely ancient. This is logical. Plants are the basis of the food pyramid for all living things even for other plants. They have always been enormously important to the welfare of people not only for food, but also for clothing, weapons, tools, dyes, medicines, shelter, and a great many other purposes. Tribes living today in the jungles of the Amazon recognize literally hundreds of plants and know many properties of each. To them, botany, as such, has no name and is probably not even recognized as a special branch of “ knowledge” at all.。
Unfortunately, the more industrialized we become the farther away we move from direct contact with plants, and the less distinct our knowledge of botany grows. Yet everyone comes unconsciously on an amazing amount of botanical knowledge, and few people will fail to recognize a rose, an apple, or an orchid. When our Neolithic ancestors, living in the Middle East about 10,000 years ago, discovered that certain grasses could be harvested and their seeds planted for richer yields the next season the first great step in a new association of plants and humans was taken. Grains were discovered and from them flowed the marvel of agriculture: cultivated crops. From then on, humans would increasingly take their living from the controlled production of a few plants, rather than getting a little here and a little there from many varieties that grew wild- and the accumulated knowledge of tens of thousands of years of experience and intimacy with plants in the wild would begin to fade away.。
33 Plankton浮游生物. / 'plжηktэn; `plжηktэn/。
Scattered through the seas of the world are billions of tons of small plants and animals called plankton. Most of these plants and animals are too small for the human eye to see. They drift about lazily with the currents, providing a basic food for many larger animals.。
Plankton has been described as the equivalent of the grasses that grow on the dry land continents, and the comparison is an appropriate one. In potential food value, however, plankton far outweighs that of the land grasses. One scientist has estimated that while grasses of the world produce about 49 billion tons of valuable carbohydrates each year, the sea’s plankton generates more than twice as much.。
Despite its enormous food potential, little effect was made until recently to farm plankton as we farm grasses on land. Now marine scientists have at last begun to study this possibility, especially as the sea’s resources loom even more important as a means of feeding an expanding world population.。
No one yet has seriously suggested that “ plankton-burgers” may soon become popular around the world. As a possible farmed supplementary food source, however, plankton is gaining considerable interest among marine scientists.。
One type of plankton that seems to have great harvest possibilities is a tiny shrimp-like creature called krill. Growing to two or three inches long, krill provides the major food for the great blue whale, the largest animal to ever inhabit the Earth. Realizing that this whale may grow to 100 feet and weigh 150 tons at maturity, it is not surprising that each one devours more than one ton of krill daily.。
34 Raising Oysters。
In the oysters were raised in much the same way as dirt farmers raised tomatoes- by transplanting them. First, farmers selected the oyster bed, cleared the bottom of old shells and other debris, then scattered clean shells about. Next, they ”planted” fertilized oyster eggs, which within two or three weeks hatched into larvae. The larvae drifted until they attached themselves to the clean shells on the bottom. There they remained and in time grew into baby oysters called seed or spat. The spat grew larger by drawing in seawater from which they derived microscopic particles of food. Before long, farmers gathered the baby oysters, transplanted them once more into another body of water to fatten them up.。
Until recently the supply of wild oysters and those crudely farmed were more than enough to satisfy people’s needs. But today the delectable seafood is no longer available in abundance. The problem has become so serious that some oyster beds have vanished entirely.。
Fortunately, as far back as the early 1900’s marine biologists realized that if new measures were not taken, oysters would become extinct or at best a luxury food. So they set up well-equipped hatcheries and went to work. But they did not have the proper equipment or the skill to handle the eggs. They did not know when, what, and how to feed the larvae. And they knew little about the predators that attack and eat baby oysters by the millions. They failed, but they doggedly kept at it. Finally, in the 1940’s a significant breakthrough was made.。
The marine biologists discovered that by raising the temperature of the water, they could induce oysters to spawn not only in the summer but also in the fall, winter, and spring. Later they developed a technique for feeding the larvae and rearing them to spat. Going still further, they succeeded in breeding new strains that were resistant to diseases, grew faster and larger, and flourished in water of different salinities and temperatures. In addition, the cultivated oysters tasted better!。
35.Oil Refining。
An important new industry, oil refining, grew after the Civil war. Crude oil, or petroleum – a dark, thick ooze from the earth – had been known for hundreds of years, but little use had ever been made of it. In the 1850’s Samuel M. Kier, a manufacturer in western Pennsylvania, began collecting the oil from local seepages and refining it into kerosene. Refining, like smelting, is a process of removing impurities from a raw material.。
Kerosene was used to light lamps. It was a cheap substitute for whale oil, which was becoming harder to get. Soon there was a large demand for kerosene. People began to search for new supplies of petroleum.。
The first oil well was drilled by E.L. Drake, a retired railroad conductor. In 1859 he began drilling in Titusville, Pennsylvania. The whole venture seemed so impractical and foolish that onlookers called it “ Drake’s Folly”. But when he had drilled down about 70 feet(21 meters), Drake struck oil. His well began to yield 20 barrels of crude oil a day.。
News of Drake’s success brought oil prospectors to the scene. By the early 1860’s these wildcatters were drilling for “ black gold” all over western Pennsylvania. The boom rivaled the California gold rush of 1848 in its excitement and Wild West atmosphere. And it brought far more wealth to the prospectors than any gold rush.。
Crude oil could be refined into many products. For some years kerosene continued to be the principal one. It was sold in grocery stores and door-to-door. In the 1880’s refiners learned how to make other petroleum products such as waxes and lubricating oils. Petroleum was not then used to make gasoline or heating oil.。
36.Plate Tectonics and Sea-floor Spreading。
The theory of plate tectonics describes the motions of the lithosphere, the comparatively rigid outer layer of the Earth that includes all the crust and part of the underlying mantle. The lithosphere(n.[地]岩石圈)is divided into a few dozen plates of various sizes and shapes, in general the plates are in motion with respect to one another. A mid-ocean ridge is a boundary between plates where new lithospheric material is injected from below. As the plates diverge from a mid-ocean ridge they slide on a more yielding layer at the base of the lithosphere.。
Since the size of the Earth is essentially constant, new lithosphere can be created at the mid-ocean ridges only if an equal amount of lithospheric material is consumed elsewhere. The site of this destruction is another kind of plate boundary: a subduction zone. There one plate dives under the edge of another and is reincorporated into the mantle. Both kinds of plate boundary are associated with fault systems, earthquakes and volcanism, but the kinds of geologic activity observed at the two boundaries are quite different.。
The idea of sea-floor spreading actually preceded the theory of plate tectonics. In its original version, in the early 1960’s, it described the creation and destruction of the ocean floor, but it did not specify rigid lithospheric plates. The hypothesis was substantiated soon afterward by the discovery that periodic reversals of the Earth’s magnetic field are recorded in the oceanic crust. As magma rises under the mid-ocean ridge, ferromagnetic minerals in the magma become magnetized in the direction of the magma become magnetized in the direction of the geomagnetic field. When the magma cools and solidifies, the direction and the polarity of the field are preserved in the magnetized volcanic rock. Reversals of the field give rise to a series of magnetic stripes running parallel to the axis of the rift. The oceanic crust thus serves as a magnetic tape recording of the history of the geomagnetic field that can be dated independently; the width of the stripes indicates the rate of the sea-floor spreading.。
37 Icebergs
Icebergs are among nature’s most spectacular creations, and yet most people have never seen one. A vague air of mystery envelops them. They come into being ----- somewhere ------in faraway, frigid waters, amid thunderous noise and splashing turbulence, which in most cases no one hears or sees. They exist only a short time and then slowly waste away just as unnoticed.。
Objects of sheerest beauty they have been called. Appearing in an endless variety of shapes, they may be dazzlingly white, or they may be glassy blue, green or purple, tinted faintly of in darker hues. They are graceful, stately, inspiring ----- in calm, sunlight seas.。
But they are also called frightening and dangerous, and that they are ---- in the night, in the fog, and in storms. Even in clear weather one is wise to stay a safe distance away from them. Most of their bulk is hidden below the water, so their underwater parts may extend out far beyond the visible top. Also, they may roll over unexpectedly, churning the waters around them.。
Icebergs are parts of glaciers that break off, drift into the water, float about awhile, and finally melt. Icebergs afloat today are made of snowflakes that have fallen over long ages of time. They embody snows that drifted down hundreds, or many thousands, or in some cases maybe a million years ago. The snows fell in polar regions and on cold mountains, where they melted only a little or not at all, and so collected to great depths over the years and centuries.。
As each year’s snow accumulation lay on the surface, evaporation and melting caused the snowflakes slowly to lose their feathery points and become tiny grains of ice. When new snow fell on top of the old, it too turned to icy grains. So blankets of snow and ice grains mounted layer upon layer and were of such great thickness that the weight of the upper layers compressed the lower ones. With time and pressure from above, the many small ice grains joined and changed to larger crystals, and eventually the deeper crystals merged into a solid mass of ice.。
38 Topaz
Topaz is a hard, transparent mineral. It is a compound of aluminum, silica, and fluorine. Gem topaz is valuable. Jewelers call this variety of the stone “precious topaz”. The best-known precious topaz gems range in color from rich yellow to light brown or pinkish red. Topaz is one of the hardest gem minerals. In the mineral table of hardness, it has a rating of 8, which means that a knife cannot cut it, and that topaz will scratch quartz.。
The golden variety of precious topaz is quite uncommon. Most of the world’s topaz is white or blue. The white and blue crystals of topaz are large, often weighing thousands of carats. For this reason, the value of topaz does not depend so much on its size as it does with diamonds and many other precious stones, where the value increases about four times with each doubling of weight. The value of a topaz is largely determined by its quality. But color is also important: blue topaz, for instance, is often irradiated to deepen and improve its color.。
Blue topaz is often sold as aquamarine and a variety of brown quartz is widely sold as topaz. The quartz is much less brilliant and more plentiful than true topaz. Most of it is variety of amethyst: that heat has turned brown.。
39 The Salinity of Ocean Waters。
If the salinity of ocean waters is analyzed, it is found to vary only slightly from place to place. Nevertheless, some of these small changes are important. There are three basic processes that cause a change in oceanic salinity. One of these is the subtraction of water from the ocean by means of evaporation--- conversion of liquid water to water vapor. In this manner the salinity is increased, since the salts stay behind. If this is carried to the extreme, of course, white crystals of salt would be left behind.。
The opposite of evaporation is precipitation, such as rain, by which water is added to the ocean. Here the ocean is being diluted so that the salinity is decreased. This may occur in areas of high rainfall or in coastal regions where rivers flow into the ocean. Thus salinity may be increased by the subtraction of water by evaporation, or decreased by the addition of fresh water by precipitation or runoff.。
Normally, in tropical regions where the sun is very strong, the ocean salinity is somewhat higher than it is in other parts of the world where there is not as much evaporation. Similarly, in coastal regions where rivers dilute the sea, salinity is somewhat lower than in other oceanic areas.。
A third process by which salinity may be altered is associated with the formation and melting of sea ice. When sea water is frozen, the dissolved materials are left behind. In this manner, sea water directly materials are left behind. In this manner, sea water directly beneath freshly formed sea ice has a higher salinity than it did before the ice appeared. Of course, when this ice melts, it will tend to decrease the salinity of the surrounding water.。
In the Weddell Sea Antarctica, the densest water in the oceans is formed as a result of this freezing process, which increases the salinity of cold water. This heavy water sinks and is found in the deeper portions of the oceans of the world.。
NOTE：
salinity / sэ'linэti; sэ`linэti/ 。
n [U] the high salinity of sea water 海水的高含盐量.。
-?>>saline / 'seilain; US -li:n; `selin/ 。
1.adj [attrib 作定语] (fml 文) containing salt; salty 含盐的; 咸的: 。
* a saline lake 盐湖 * saline springs 盐泉 。
* saline solution, eg as used for gargling, storing contact lenses, etc 盐溶液（如用于漱喉、存放隐形眼镜等）.。
2. n [U] (medical 医) solution of salt and water 盐水.。
40 Cohesion-tension Theory。
Atmospheric pressure can support a column of water up to 10 meters high. But plants can move water much higher; the sequoia tree can pump water to its very top more than 100 meters above the ground. Until the end of the nineteenth century, the movement of water in trees and other tall plants was a mystery. Some botanists hypothesized that the living cells of plants acted as pumps. But many experiments demonstrated that the stems of plants in which all the cells are killed can still move water to appreciable heights. Other explanations for the movement of water in plants have been based on root pressure, a push on the water from the roots at the bottom of the plant. But root pressure is not nearly great enough to push water to the tops of tall trees. Furthermore, the conifers, which are among the tallest trees, have unusually low root pressures.。