第一篇：
Chinese Population Growth
Increases in population have usually been accompanied (indeed facilitated) by an increase in trade. In the Western experience, commerce provided the conditions that allowed industrialization to get started, which in turn led to growth in science, technology, industry, transport, communications, social change, and the like that we group under the broad term of “development.” However, the massive increase in population that in Europe was at first attributed to industrialization starting in the eighteenth century occurred also and at the same period in China, even though there was no comparable industrialization.
It is estimated that the Chinese population by 1600 was close to 150 million. The transition between the Ming and Qing dynasties (the seventeenth century) may have seen a decline, but from 1741 to 1851 the annual figures rose steadily and spectacularly, perhaps beginning with 143 million and ending with 432 million. If we accept these totals, we are confronted with a situation in which the Chinese population doubled in the 50 years from 1790 to 1840. If, with greater caution, we assume lower totals in the early eighteenth century and only 400 million in 1850, we still face a startling fact: something like a doubling of the vast Chinese population in the century before Western contact, foreign trade, and industrialization could have had much effect.
To explain this sudden increase we cannot point to factors constant in Chinese society but must find conditions or a combination of factors that were newly effective in this period. Among these is the almost complete internal peace maintained under Manchu rule during the eighteenth century. There was also an increase in foreign trade through Guangzhou (southern China) and some improvement of transportation within the empire. Control of disease, like the checking of smallpox by variolation may have been important. But of most critical importance was the food supply.
Confronted with a multitude of unreliable figures, economists have compared the population records with the aggregate data for cultivated land area and grain production in the six centuries since 1368. Assuming that China’s population in 1400 was about 80 million, the economist Dwight Perkins concludes that its growth to 700 million or more in the 1960s was made possible by a steady increase in the grain supply, which evidently grew five or six times between 1400 and 1800 and rose another 50 percent between 1800 and 1965. This increase of food supply was due perhaps half to the increase of cultivated area, particularly by migration and settlement in the central and western provinces, and half to greater productivity—the farmers’ success in raising more crops per unit of land.
This technological advance took many forms: one was the continual introduction from the south of earlier-ripening varieties of rice, which made possible double-cropping (the production of two harvests per year from one field). New crops such as corn (maize) and sweet potatoes as well as peanuts and tobacco were introduced from the Americas. Corn, for instance, can be grown on the dry soil and marginal hill land of North China, where it is used for food, fuel, and fodder and provides something like one-seventh of the food energy available in the area. The sweet potato, growing in sandy soil and providing more food energy per unit of land than other crops, became the main food of the poor in much of the South China rice area.
Productivity in agriculture was also improved by capital investments, first of all in irrigation. From 1400 to 1900 the total of irrigated land seems to have increased almost three times. There was also a gain in farm tools, draft animals, and fertilizer, to say nothing of the population growth itself, which increased half again as fast as cultivated land area and so increased the ratio of human hands available per unit of land. Thus the rising population was fed by a more intensive agriculture, applying more labor and fertilizer to the land.
参考译文
中国的人口增长
人口增长通常伴随着(事实上促进了)贸易的增加。按照西方社会的经验，商业为工业化的开始提供了条件，而工业化反过来又促进了科学、技术、工业、交通运输、通信进步、社会变化和所有我们归结为“发展”方面的进步。但是，十八世纪开始的工业化带来了欧洲的人口大幅增长;同时间中国的人口也暴涨，尽管中国没有经历类似的工业化。
据估计，到1600年中国的人口已经接近1亿5000万。明清之交(十七世纪)人口数量可能有所减少，但从1741年到1851年，人口数量每年都稳步显著地上升，从1亿4300万涨到了4亿3200万。如果我们认为这些统计数据真实有效，我们将面临这样一个情形：从1790年到1840年，中国人口在这50年间翻了一番。如果我们对这些统计数据的真实性谨慎一些，我们假设在18世纪初总人数要少一些，到1850年也只有4亿的话，事实依然让人吃惊：在与西方接触、对外贸易和工业化之前，像中国这样庞大的人口数量翻倍增长的因素本应像西方一样对社会产生很大的影响的。
要解释这种突然的人口增加，我们不能直指中国社会的一些一直不变的因素，而是必须找到当时在那一时期新出现的有影响力的一系列条件或诸多组合因素。其中包括：十八世纪的中国处于满族统治下，国内几乎完全和平;广州(华南)的对外贸易也有所增加，国家内部的交通运输也有所改善;还有一个重要因素是疾病的控制，如通过人痘接种来克制天花。但这当中最重要的还是粮食供应。
面对大量的不可靠的数据，经济学家将1368年以来的6个世纪的人口统计记录与耕地面积和粮食生产总量的综合数据进行了比较。假设在1400年中国的人口是8000万左右，：由于粮食产量稳步增长，到20世纪60年代人口是有可能增长到7亿人的，明显地从1400年到1800年增长了5到6倍，从1800年到1965年又增长了50%。粮食供应的增加可能一半是由于耕地面积的增加，特别是因为移民和定居到中西部省份带来的耕地面积增加;另一半是由于生产力的提高——农民成功提高了每单位土地面积的粮食产量。
技术进步有许多形式：一个是不断从南方引进早熟的水稻品种，这种水稻可以一年两熟(一块地每年收获两季)。新作物如玉米、红薯、花生和烟草从美洲传进来。拿玉米来说，可以在干燥的土壤和华北边缘的山地种植，可用作食品、燃料、饲料，提供了当地七分之一的食物能量。红薯可以在沙质土壤中种植，由于每单位土地面积提供的食物能量比其他作物都多，所以成为了很多华南水稻种植地区穷人们的主要食品。
资本的投入也提高了农业生产力。首先是灌溉方面，从1400年到1900年，总灌溉土地似乎增加了近三倍。农用工具、役畜和肥料方面都有进步，更不用说人口本身也有增长，增速是耕地面积增速的一半，因此增加了单位土地面积上的劳动力比例。这种更加密集的农业生产为增长的人口提供食物，而人口为土地提供更多的劳动力和肥料。
第二篇：
Determining Dinosaur Diet
Determining what extinct dinosaurs ate is difficult, but we can infer some aspects of their dietary preferences. Traditionally, this information has been derived from direct evidence, such as stomach contents, and indirect evidence, such as establishing a correlation between particular body characteristics and diets of living animals and then inferring habits for dinosaurs.
Animals such as house cats and dogs have large, stabbing canine teeth at the front of the mouth and smaller, equally sharp teeth farther back in their jaws. Many of these animals are also armed with sharp claws. The advantage of teeth and claws as predatory tools is obvious. Now consider animals like cows, horses, rabbits, and mice. These animals have flat teeth at the back of the jaw that are analogous to and have the same function as grindstones. Unlike the meat-slicing and stabbing teeth of carnivores, the teeth of these animals grind and shred plant material before digestion.
More clues exist in other parts of the skull. The jaw joint of carnivores such as dogs and cats has the mechanical advantage of being at the same level as the tooth row, allowing the jaws to close with tremendous speed and forcing the upper teeth to occlude against the lower teeth with great precision. In herbivorous animals, rapid jaw closure is less important. Because the flat teeth of herbivores work like grindstones, however, the jaws mush move both side to side and front to back. The jaw joints of many advanced herbivores, such as cows, lie at a different level than the tooth row, allowing transverse tearing, shredding, and compression of plant material. If we extend such observations to extinct dinosaurs, we can infer dietary preferences (such as carnivory and herbivory), even though we cannot determine the exact diet. The duck-billed dinosaurs known as hadrosaurs are a good example of a group whose jaw joint is below the level of the tooth row, which probably helped them grind up tough, fibrous vegetation.
Paleontologists would like to be much more specific about a dinosaur’s diet than simply differentiating carnivore from herbivore. This finer level of resolution requires direct fossil evidence of dinosaur meals. Stomach contents are only rarely preserved, but when present, allow us to determine exactly what these animals were eating.
In the stomach contents of specimens of Coelophysis (a small, long-necked dinosaur) are bones from juvenile animals of the same species. At one time, these were thought to represent embryonic animals, suggesting that this small dinosaur gave birth to live young rather than laying eggs. Further research indicated that the small dinosaurs were too large and too well developed to be prehatchling young. In addition, the juveniles inside the body cavity were of different sizes. All the evidence points to the conclusion that these are the remains of prey items and that, as an adult, Coelophysis was at least in part a cannibal.
Fossilized stomach contents are not restricted to carnivorous dinosaurs. In a few rare cases, most of them “mummies” (unusually well preserved specimens), fossilized plant remains have been found inside the body cavity of hadrosaurs. Some paleontologists have argued that these represent stream accumulations rather than final meals. The best known of these cases is the second Edmontosaurus mummy collected by the Sternbergs. In the chest cavity of this specimen, which is housed in the Senckenberg Museum in Germany, are the fossil remains of conifer needles, twigs, seeds, and fruits. Similar finds in Corythosaurus specimens from Alberta, Canada, have also been reported, indicating that at least two kinds of Late Cretaceous hadrosaurs fed on the sorts of tress that are common in today’s boreal woodlands.
A second form of direct evidence comes from coprolites (fossilized bodily waste). Several dinosaur fossil localities preserve coprolites. Coprolites yield unequivocal evidence about the dietary habits of dinosaurs. Many parts of plants and animals are extremely resistant to the digestive systems of animals and pass completely through the body with little or no alteration. Study of coprolites has indicated that the diets of some herbivorous dinosaurs were relatively diverse, while other dinosaurs appear to have been specialists, feeding on particular types of plants. The problem with inferring diets from coprolites is the difficulty in accurately associating a particular coprolite with a specific dinosaur.
参考译文
确定恐龙的饮食
要确定已经灭绝的恐龙吃什么是一件很困难的事情，但是我们能推测出它们在饮食上的一些偏好。通常，这些信息可以从直接证据获得，比如说胃内食物，以及间接证据，如通过在恐龙的特定身体特征和现今存活的动物的饮食习惯之间建立关系来推断恐龙的饮食习惯。
像家养的猫和狗这类动物，嘴前部的牙齿又大又尖，后部的牙齿要小一些但是同样锋利。这些动物中有许多都有着锋利的爪子。牙齿和爪子作为捕食工具的优势非常明显。现在再看牛、马、兔子和老鼠这些动物。它们后部的牙齿比较扁平，功能类似于研磨的石头。不像食肉动物的牙齿是刺进肉里并把肉撕开，这些动物的牙齿会将植物磨成碎块再消化。
头骨的其他部分存在更多线索。狗和猫这类食肉动物的颌关节和牙齿在同一高度上，这种机械上的优势能使上下颌快速闭合，使得上下牙齿咬合严密。对草食动物来说，快速颌闭合并不那么重要。由于食草动物的扁平牙齿像磨刀石一般，然而它们的上下颌可以前后左右移动来粉碎食物。许多高等草食动物，如牛，颌关节和牙齿的高度并不一致，但是这样它们就能横向撕裂、切碎和挤压植物。如果我们把这种观察方法应用到灭绝的恐龙身上，我们可以推断出恐龙的饮食偏好(如肉食还是草食)，虽然我们无法确定准确的食物。鸭嘴龙便是一个颌关节比牙齿低的例子，这种高度不一致可能会帮助它们把坚韧的纤维植物磨碎。
古生物学家不只是想要区分恐龙是食草还是吃肉，他们还想知道恐龙的具体饮食。这种更精细的研究决心需要直接的恐龙食物的化石证据。胃里的食物很少能保存，但如果有，就能让我们确定恐龙到底吃什么。
腔骨龙(一种体型较小、脖子较长的恐龙)的胃内食物样本是同类恐龙的幼崽骨头。科学家一度认为这些幼崽骨头属于腔骨龙的胚胎，认为这种小恐龙是胎生而非卵生。进一步的研究发现，这些幼崽体积太大，而且发育良好，不可能是孵化前的幼崽。另外，这些胃内的幼崽残骸大小也不一。所有的证据都表明，这些都是猎物的残骸，成年腔骨龙中至少有一部分是吃自己的同类的。
并非只有食肉恐龙才有胃内食物的化石。在一些罕见的情况下，鸭嘴龙的体内也发现有植物遗骸的化石或“木乃伊”(罕见的保存完好的标本)。一些古生物学家认为，这些食物是积累下来的食物而不是最后一餐。最著名的案例是施特恩伯格一家收集的第二具埃德蒙顿木乃伊。标本存放在德国森肯伯格博物馆内，在其胸腔内，是针叶、细枝、种子和果实的化石。加拿大阿尔伯塔的冠龙标本也报导了类似的发现，这表明至少有两种晚白垩纪的鸭嘴龙是以现在北半球森林中的常见树木为食的。
另一个直接的证据形式来自粪化石(身体排泄物的化石)。几个恐龙化石地点保存有粪化石。粪化石能明确说明恐龙的饮食习惯。很多植物和动物不容易被动物的消化系统消化，没有改变或者只有些许改变就排出体内了。对粪化石的研究表明，有些食草恐龙的饮食比较多样化，而另一些恐龙似乎专门吃某些特定的食物。从粪化石推断饮食偏好，困难在于如何准确知道哪种粪化石属于哪种特定的恐龙。
第三篇：
Climate and Urban Development
For more than a hundred years, it has been known that cities are generally warmer than surrounding rural areas. This region of city warmth, known as the urban heat island, can influence the concentration of air pollution. However, before we look at its influence, let’s see how the heat island actually forms.
The urban heat island is due to industrial and urban development. In rural areas, a large part of the incoming solar energy is used in evaporating water from vegetation and soil. In cities, where less vegetation and exposed soil exist, the majority of the Sun’s energy is absorbed by urban structures and asphalt. Hence, during warm daylight hours, less evaporative cooling in cities allows surface temperatures to rise higher than in rural areas. The cause of the urban heat island is quite involved. Depending on the location, time of year, and time of day, any or all of the following differences between cities and their surroundings can be important: albedo (reflectivity of the surface), surface roughness, emissions of heat, emissions of moisture, and emissions of particles that affect net radiation and the growth of cloud droplets.
At night, the solar energy (stored as vast quantities of heat in city buildings and roads) is slowly released into the city air. Additional city heat is given off at night (and during the day) by vehicles and factories, as well as by industrial and domestic heating and cooling units. The release of heat energy is retarded by the tall vertical city walls that do not allow infrared radiation to escape as readily as does the relatively level surface of the surrounding countryside. The slow release of heat tends to keep nighttime city temperatures higher than those of the faster-cooling rural areas. Overall, the heat island is strongest (1) at night when compensating sunlight is absent; (2) during the winter, when nights are longer and there is more heat generated in the city; and (3) when the region is dominated by a high-pressure area with light winds, clear skies, and less humid air. Over time, increasing urban heat islands affect climatological temperature records, producing artificial warming in climatic records taken in cities. This warming, therefore, must be accounted for in interpreting climate change over the past century.
The constant outpouring of pollutants into the environment may influence the climate of the city. Certain particles reflect solar radiation, thereby reducing the sunlight that reaches the surface. Some particles serve as nuclei upon which water and ice form. Water vapor condenses onto these particles when the relative humidity is as low as 70 percent, forming haze that greatly reduces visibility. Moreover, the added nuclei increase the frequency of city fog.
Studies suggest that precipitation may be greater in cities than in the surrounding countryside; this phenomenon may be due in part to the increased roughness of city terrain, brought on by large structures that cause surface air to slow and gradually converge. This piling up of air over the city then slowly rises, much like toothpaste does when its tube is squeezed. At the same time, city heat warms the surface air, making it more unstable, which enhances risings air motions, which, in turn, aids in forming clouds and thunderstorms. This process helps explain why both tend to be more frequent over cities.
On clear still nights when the heat island is pronounced, a small thermal low-pressure area forms over the city. Sometimes a light breeze—called a country breeze—blows from the countryside into the city. If there are major industrial areas along the outskirts, pollutants are carried into the heat of town, where they tend to concentrate. Such an event is especially probable if vertical mixing and dispersion of pollutants are inhibited. Pollutants from urban areas may even affect the weather downwind from them.
参考译文
气候与城市发展
一百多年来，人们都知道城市一般比周围的农村地区温度高些。这种地区性的城市温度升高，被称为城市热岛，可以影响空气污染的浓度。然而，在我们考虑它的影响之前，让我们先看看热岛实际上是如何形成的。
城市热岛的成因是工业和城市发展。在农村地区，很大一部分的太阳能被用于从植被和土壤中蒸发水分。城市中植被稀少、土壤裸露，大部分的太阳能被城市建筑和沥青路面吸收。因此，在温暖的白天，城市的蒸发散热较少，地表温度就比农村地区高。城市热岛的成因很复杂。位置、季节、一天当中的时间不同，以及城市和周围的环境之间的任何差异都可能是重要影响因素：比如反照率(地表反射率)、地表粗糙度、散热量、湿度排放，影响净辐射的微粒量排放和云滴的增长。
在夜间，太阳能(储存在城市建筑和道路的巨大热量)被慢慢释放到城市空气中。另外，城市的车辆、工厂、以及工业用和家用的制热和制冷系统也在夜间(和白天)释放出热量。释放出来的热能被高耸的城市墙所阻碍，使得红外线无法像周围的乡村相对较为平坦的地面那样容易散去。由于热量释放缓慢，使得城市夜间的温度比容易散热的农村地区要高。总体而言，热岛效应在三种情况下最强：(1)没有太阳光照射补给的夜间;(2)夜晚较长、城市产生更多热量的冬季;(3)微风、晴朗、干燥的高气压地区。随着时间的推移，城市热岛效应影响了气象学上的温度记录，导致了人为热岛效应的温度升高被记录在城市气候记录上;因此，理解过去一个世纪以来的气候变化必须要考虑这种变暖带来的影响。
不断向环境排放污染气体可能影响城市气候。某些粒子会反射太阳辐射，从而减少到达地面的阳光。有些粒子是形成水和冰的凝结核。当相对湿度低至70%时，水蒸气凝结在这些粒子上，就会形成阴霾，大大降低能见度。此外，凝结核的增加会增加城市出现雾的频率。
研究表明，城市的降水可能要比周边农村地区要多;出现这种现象的部分原因可能是大型建筑物使得地表空气缓慢、逐渐地汇聚在一起，使得城市地形高低不平的程度增加。城市上空堆积的空气慢慢地上升，就像挤牙膏一样。同时，城市的热量使空气受热，变得更加不稳定，这有加强了气流的上升运动，反过来有助于形成云或雷雨。这个过程帮助解释了为什么城市的云和雷雨更频繁。
在晴朗平静的夜晚，热岛效应明显，城市会形成一个小的热低压区。有时微风——乡村风会从农村吹进城市。如果郊区沿线有大工业区，污染物被带入城市的中心，污染物就会更加聚集。如果污染物在垂直方向上不能混合或者扩散的话，就更容易聚集了。从城市地区吹来的污染物甚至可以影响到它们的顺风方向的天气。
托福TPO40阅读原文及译文
第一篇：Ancient Athens
One of the most important changes in Greece during the period from 800 B.C. to 500 B.C. was the rise of the polis, or city-state, and each polis developed a system of government that was appropriate to its circumstances. The problems that were faced and solved in Athens were the sharing of political power between the established aristocracy and the emerging other classes, and the adjustment of aristocratic ways of life to the ways of life of the new polis. It was the harmonious blending of all of these elements that was to produce the classical culture of Athens.
Entering the polis age, Athens had the traditional institutions of other Greek protodemocratic states: an assembly of adult males, an aristocratic council, and annually elected officials. Within this traditional framework the Athenians, between 600 B.C. and 450 B. C., evolved what Greeks regarded as a fully fledged democratic constitution, though the right to vote was given to fewer groups of people than is seen in modem times.
The first steps toward change were taken by Solon in 594 B. C.，when he broke the aristocracy's stranglehold on elected offices by establishing wealth rather than birth as the basis of office holding, abolishing the economic obligations of ordinary Athenians to the aristocracy, and allowing the assembly (of which all citizens were equal members) to overrule the decisions of local courts in certain cases. The strength of the Athenian aristocracy was further weakened during the rest of the century by the rise of a type of government known as a tyranny, which is a form of interim rule by a popular strongman (not rule by a ruthless dictator as the modern use of the term suggests to us). The Peisistratids, as the succession of tyrants were called (after the founder of the dynasty, Peisistratos), strengthened Athenian central administration at the expense of the aristocracy by appointing judges throughout the region, producing Athens’ first national coinage, and adding and embellishing festivals that tended to focus attention on Athens rather than on local villages of the surrounding region. By the end of the century, the time was ripe for more change: the tyrants were driven out, and in 508 B C a new reformer, Cleisthenes, gave final form to the developments reducing aristocratic control already under way.
Cleisthenes' principal contribution to the creation of democracy at Athens was to complete the long process of weakening family and clan structures, especially among the aristocrats, and to set in their place locality-based corporations called demes, which became the point of entry for all civic and most religious life in Athens. Out of the demes were created 10 artificial tribes of roughly equal population. From the demes, by either election or selection, came 500 members of a new council, 6,000 jurors for the courts, 10 generals, and hundreds of commissioners. The assembly was sovereign in all matters but in practice delegated its power to subordinate bodies such as the council, which prepared the agenda for the meetings of the assembly, and me courts, which took care of most judicial matters. Various committees acted as an executive branch, implementing policies of the assembly and supervising, for instance, the food and water supplies and public buildings. This wide-scale participation by the citizenry in the government distinguished the democratic form of the Athenian polis from other, less liberal forms.
The effect of Cleisthenes’ reforms was to establish the superiority of the Athenian community as a whole over local institutions without destroying them. National politics rather than local or deme politics became the focal point. At the same time, entry into national politics began at the deme level and gave local loyalty a new focus: Athens itself. Over the next two centuries the implications of Cleisthenes’ reforms were fully exploited.
During the fifth century B. C. the council of 500 was extremely influential in shaping policy. In the next century, however, it was the mature assembly that took on decision-making responsibility. By any measure other than that of the aristocrats, who had been upstaged by the supposedly inferior "people," the Athenian democracy was a stunning success. Never before, or since, have so many people been involved in the serious business of self-governance. It was precisely this opportunity to participate in public life that provided a stimulus for the brilliant unfolding of classical Greek culture.
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