托福机经真题2013年3月22日及答案解析.doc

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1、托福机经真题 2013 年 3 月 22 日及答案解析(总分：11.00，做题时间：120 分钟)听力1.Conversation 1：【对话-服务咨询-食堂】 要点： 有个 Cafeteria Manager 跟女学生的对话; 女学生要搬出去，不住 dorm，想把 Meal Plan 取消。但是 Manager 说一旦买了就不可以取消; 然后讲了一大堆他们 Cafeteria 的食物有多好，有新菜等等; 后来女学生问他有没有别的办法，他说能咨询一下是否能把 Meal Plan 转到其他 Building 的 Cafe.（分数：1.00）_2.Lecture 1：【讲座-社会科学-历史】 世界

2、历史，讲 tea trade between Asia tea 在什么时候到哪里的，一开始先到荷兰;再到英国，在英国广泛流传; 一开始只有达官贵族能喝到 tea,后来 tea 又用来当药用;之后有个 princess(忘记名字了，会有提示)教群众如何将 tea 变得没那么苦。后来又发明将糖加到 tea 里面会很好喝; 也说了 coffee 没有广泛被需要的原因，是生产shortage，问的是 culture trend 的相关问题。（分数：1.00）_3.Lecture 2：【讲座-艺术-艺术家】 Art, 近代美国艺术家 child Hassam 作品 the breakfast room,

3、 winter morning, 1911，说他的作品受环境的影响。（分数：1.00）_阅读4.第一篇: 地质学，讲的是大气如何形成 (注：此篇可结合 TPO16 的第三篇 Planets in our solar system 中与大气相关内容阅读) Atmosphere Atmosphere, mixture of gases surrounding any celestial object that has a gravitational field strong enough to prevent the gases from escaping; especially the gase

4、ous envelope of Earth. The principal constituents of the atmosphere of Earth are nitrogen (78 percent) and oxygen (21 percent). The atmospheric gases in the remaining 1 percent are argon (0.9 percent), carbon dioxide (0.03 percent), varying amounts of water vapor, and trace amounts of hydrogen, ozon

5、e, methane, carbon monoxide, helium, neon, krypton, and xenon. The mixture of gases in the air today has had 4.5 billion years in which to evolve. The earliest atmosphere must have consisted of volcanic emanations alone. Gases that erupt from volcanoes today, however, are mostly a mixture of water v

6、apor, carbon dioxide, sulfur dioxide, and nitrogen, with almost no oxygen. If this is the same mixture that existed in the early atmosphere, then various processes would have had to operate to produce the mixture we have today. One of these processes was condensation. As it cooled, much of the volca

7、nic water vapor condensed to fill the earliest oceans. Chemical reactions would also have occurred. Some carbon dioxide would have reacted with the rocks of Earths crust to form carbonate minerals, and some would have become dissolved in the new oceans. Later, as primitive life capable of photosynth

8、esis evolved in the oceans, new marine organisms began producing oxygen. Almost all the free oxygen in the air today is believed to have formed by photosynthetic combination of carbon dioxide with water. About 570 million years ago, the oxygen content of the atmosphere and oceans became high enough

9、to permit marine life capable of respiration. Later, some 400 million years ago, the atmosphere contained enough oxygen for the evolution of air-breathing land animals. The water-vapor content of the air varies considerably, depending on the temperature and relative humidity. With 100 percent relati

10、ve humidity, the water-vapor content of air varies from 190 parts per million (ppm) at -40C (-40F) to 42,000 ppm at 30C (86F). Minute quantities of other gases, such as ammonia, hydrogen sulfide, and oxides of sulfur and nitrogen, are temporary constituents of the atmosphere in the vicinity of volca

11、noes and are washed out of the air by rain or snow. Oxides and other pollutants added to the atmosphere by industrial plants and motor vehicles have become a major concern, however, because of their damaging effects in the form of acid rain. In addition, the strong possibility exists that the steady

12、 increase in atmospheric carbon dioxide, mainly as the result of the burning of fossil fuels since the mid-1800s, may affect Earths climate (see Greenhouse Effect). Similar concerns are posed by the sharp increase in atmospheric methane. Methane levels have risen 11 percent since 1978. About 80 perc

13、ent of the gas is produced by decomposition in rice paddies, swamps, and the intestines of grazing animals, and by tropical termites. Human activities that tend to accelerate these processes include raising more livestock and growing more rice. Besides adding to the greenhouse effect, methane reduce

14、s the volume of atmospheric hydroxyl ions, thereby curtailing the atmospheres ability to cleanse itself of pollutants. See also Air Pollution; Climate; Smog. The study of air samples shows that up to at least 88 km (55 mi) above sea level the composition of the atmosphere is substantially the same a

15、s at ground level; the continuous stirring produced by atmospheric currents counteracts the tendency of the heavier gases to settle below the lighter ones. In the lower atmosphere, ozone, a form of oxygen with three atoms in each molecule, is normally present in extremely low concentrations. The lay

16、er of atmosphere from 19 to 48 km (12 to 30 mi) up contains more ozone, produced by the action of ultraviolet radiation from the sun. Even in this layer, however, the percentage of ozone is only 0.001 by volume. Atmospheric disturbances and downdrafts carry varying amounts of this ozone to the surfa

17、ce of Earth. Human activity adds to ozone in the lower atmosphere, where it becomes a pollutant that can cause extensive crop damage. The ozone layer became a subject of concern in the early 1970s, when it was found that chemicals known as chlorofluorocarbons (CFCs), or chlorofluoromethanes, were ri

18、sing into the atmosphere in large quantities because of their use as refrigerants and as propellants in aerosol dispensers. The concern centered on the possibility that these compounds, through the action of sunlight, could chemically attack and destroy stratospheric ozone, which protects Earths sur

19、face from excessive ultraviolet radiation. As a result, industries in the United States, Europe, and Japan replaced chlorofluorocarbons in all but essential uses. See Aerosol Dispenser; Ozone Layer; Photochemistry. The atmosphere may be divided into several layers. In the lowest one, the troposphere

20、, the temperature as a rule decreases upward at the rate of 5.5C per 1,000 m (3F per 3,000 ft). This is the layer in which most clouds occur (see Cloud). The troposphere extends up to about 16 km (about 10 mi) in tropical regions (to a temperature of about -79C, or about -110F) and to about 9.7 km (

21、about 6 mi) in temperate latitudes (to a temperature of about -51C, or about -60F). Above the troposphere is the stratosphere. In the lower stratosphere the temperature is practically constant or increases slightly with altitude, especially over tropical regions. Within the ozone layer the temperatu

22、re rises more rapidly, and the temperature at the upper boundary of the stratosphere, almost 50 km (about 30 mi) above sea level, is about the same as the temperature at the surface of Earth. The layer from 50 to 90 km (30 to 55 mi), called the mesosphere, is characterized by a marked decrease in te

23、mperature as the altitude increases. From investigations of the propagation and reflection of radio waves, it is known that beginning at an altitude of 60 km (40 mi), ultraviolet radiation, X rays (see X Ray), and showers of electrons from the sun ionize several layers of the atmosphere, causing the

24、m to conduct electricity; these layers reflect radio waves of certain frequencies back to Earth. Because of the relatively high concentration of ions in the air above 60 km (40 mi), this layer, extending to an altitude of about 1000 km (600 mi), is called the ionosphere. At an altitude of about 90 k

25、m (55 mi), temperatures begin to rise. The layer that begins at this altitude is called the thermosphere, because of the high temperatures reached in this layer (about 1200C, or about 2200F). The region beyond the thermosphere is called the exosphere, which extends to about 9,600 km (about 6,000 mi)

26、, the outer limit of the atmosphere. The density of dry air at sea level is about 1/800 the density of water; at higher altitudes it decreases rapidly, being proportional to the pressure and inversely proportional to the temperature. Pressure is measured by a barometer and is expressed in millibars,

27、 which are related to the height of a column of mercury that the air pressure will support; 1 millibar equals 0.75 mm (0.03 in) of mercury. Normal atmospheric pressure at sea level is 1,013 millibars, that is, 760 mm (29.92 in) of mercury. At an altitude of 5.6 km (about 3.5 mi) pressure falls to ab

28、out 507 millibars (about 380 mm/14.96 in of mercury); half of all the air in the atmosphere lies below this level. The pressure is approximately halved for each additional increase of 5.6 km in altitude. At 80 km (50 mi) the pressure is 0.009 millibars (0.0069 mm/0.00027 in of mercury).（分数：1.00）_5.第

29、二篇： 生物学，果蝇和青蛙成长的不同时期需要什么（分数：1.00）_6.第三篇： bird nesting,说鸟喜欢在 colonies 筑巢，说了有什么好处，有一种鸟有自我保护意思，可以群体攻击那些天敌，有些 seabird 都在哪里筑巢比较安全，同时，集体筑巢又有什么隐患，例如吸引大量天敌。etc. Bird Nesting Colonies In many species, including herons, swallows, and most seabirds, individual birds come together each year to build nests near

30、the nests of many others of the species. The resulting aggregations are called nesting colonies. Colonial nesting involves a number of factors. Seabirds, for example, often forage widely over the ocean surface, where the only available nesting land may be an island of limited area. The birds may als

31、o prefer an island to mainland nesting sites because it is safer, being inaccessible to most land predators. Also, by watching their neighbors returning to the colony with food for their chicks, colony-nesting gulls, or puffins may learn from one another where they can forage most successfully. Bank

32、 and Cliff Swallows, for example, build their nests in sites protected from ground predators such as foxes, skunks, and weasels. Because residents in a colony usually share their feeding sites, colonial nesters are not, strictly speaking, territorial birds. They do, however, defend their nests again

33、st the adjacent birds, and with good reason: Colony members are known to sometimes steal nesting material from one another. They have also been known to sneak eggs into other birds nests and to seduce other birds mates. On the positive side, a few colony nesters have been known, on rare occasions, t

34、o feed another neighbors chicks. Bird Colonies The habit of nesting in groups is believed to provide better survival against predators in several ways. Many colonies are situated in locations that are naturally free of predators. In other cases, the presence of many birds means there are more indivi

35、duals available for defense. Also, synchronized breeding leads to such an abundance of offspring as to satiate predators. For seabirds, colonies on islands have an obvious advantage over mainland colonies when it comes to protection from terrestrial predators. Other situations can also be found wher

36、e bird colonies avoid predation. A study of Yellow-rumped Caciques in Peru found that the birds, which build enclosed, pouch-like nests in colonies of up to one hundred active nests, situate themselves near wasp nests, which provide some protection from tree-dwelling predators such as monkeys. When

37、other birds came to rob the nests, the caciques would cooperatively defend the colony by mobbing the invader. Mobbing, clearly a group effort, is well-known behavior, not limited to colonial species; the more birds participating in the mobbing, the more effective it is at driving off the predator. T

38、herefore, it has been theorized that the larger number of individuals available for vigilance and defense makes the colony a safer place for the individual birds nesting there. More pairs of eyes and ears are available to raise the alarm and rise to the occasion. Another suggestion is that colonies

39、act as information centers and birds that have not found good foraging sites are able to follow others, who have fared better, to find food. This makes sense for foragers because the food source is one that can be locally abundant. This hypothesis would explain why the Lesser Kestrel, which feeds on

40、 insects, breeds in colonies, while the related Common Kestrel, which feeds on larger prey, is not. Colonial behaviour has its costs as well. It has been noted that parasitism by haematozoa is higher in colonial birds and it has been suggested that blood parasites might have shaped adaptations such

41、as larger organs in the immune system and life-history traits. Other costs include brood parasitism and competition for food and territory. Colony size is a factor in the ecological function of colony nesting. In a larger colony, increased competition for food can make it harder for parents to feed

42、their chicks. The benefits and drawbacks for birds of nesting in groups seem to be highly situational. Although scientists have hypothesized about the advantages of group nesting in terms of enabling group defensive behavior, escape from predation by being surrounded by neighbors (called the selfish

43、 herd hypothesis), as well as escaping predators through sheer numbers, in reality, each of these functions evidently depends on a number of factors. Clearly, there can be safety in numbers, but there is some doubt about whether it balances out against the tendency for conspicuous breeding colonies

44、to attract predators, and some suggest that colonial breeding can actually make birds more vulnerable. At a Common Tern colony in Minnesota, a study of Spotted Sandpipers observed to nest near the tern colony showed that the sandpipers that nested nearest the colony seemed to gain some protection fr

45、om mammalian predators, but avian predators were apparently attracted to the colony and the sandpipers nesting there were actually more vulnerable. In a study of a Least Tern colony in Connecticut, nocturnal avian predators in the form of Black-crowned Night Herons and Great Horned Owls were observe

46、d to repeatedly invade a colony, flying into the middle of the colony and meeting no resistance. For seabirds, the location of colonies on islands, which are inaccessible to terrestrial predators, is an obvious advantage. Islands where terrestrial predators have arrived in the form of rats, cats, fo

47、xes, etc., have devastated island seabird colonies. One well-studied case of this phenomenon has been the effect on Common Murre colonies on islands in Alaska, where foxes were introduced for fur farming.（分数：1.00）_写作7.综合写作： dental amalgam Reading 提到三点，对人，环境的不好，以及其他替补的可能性; lecture 也提到三点，对人， 对环境 如何保护，以及其他 material 性价比不够 amalgam 好;（分数：1.00）_8.独立写作： Do you agree or disagree with the following statement? Though modern agricultural practices damage the environment, feeding the worlds growing population is more important