2014年3月16日中国大陆托福考试全真试题英文还原

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　　①Social animal and solitary animal

　　Social animals are those animals which interact highly with other animals, usually of their own species, to the point of having a recognizable and distinct society. The interactions and socializing will help to develop emotional stability and flexibility for the span of the animals' life. Solitary animals are those that spend a majority of their lives without others of their species, with possible exceptions for mating and raising their young. On the contrary, animals that are solitary are often territorial and do not like the company of another animal in their territory and especially an animal of their own kind. This could be due to competition between rivals for the opportunity to mate or over territory, or it could be a more suitable way to live in the environment. When two of the same species meet they often show aggressive displays to try to chase off the other, but if neither of the two backs down a brawl can escalate. In some species these fights can end in the death of one or both animals. Both living models of animals have their benefits and weakness.

　　The benefits of social animals is that they can rely on each other. Swallows always settle up their nests besides their partners, which can follow them to find good feeding site. The penguins also have this living habit. They are always closed to each other in order to keep themselves warm. On the other side, living together has potential danger to social animals. Bees all live in the honeycomb, which means that one sick bee can lead to a collective disease to all bees in the comb. This is the cost of social living.

　　It is comprehensible that animals choose their preferred living models based on their self condition. Since the shapes of mouth are different, some birds chooses to live together; however, sunfishes have quite huge jaw which can fight the rivals, so they choose to live alone.

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　　A comet is an icy small Solar System body that, when passing close to the Sun, heats up and begins to outgas, displaying a visible atmosphere or coma, and sometimes also a tail. These phenomena are due to the effects of solar radiation and the solar wind upon the nucleus of the comet. Comet nuclei range from a few hundred metres to tens of kilometers across and are composed of loose collections of ice, dust, and small rocky particles. The coma and tail are much larger, and if sufficiently bright may be seen from the Earth without the aid of a telescope. Hyperbolic comets may pass once through the inner Solar System before being flung out to interstellar space along hyperbolic trajectories.

　　Comets are distinguished from asteroids by the presence of an extended, gravitationally unbound atmosphere surrounding their central nucleus. This atmosphere has parts termed the coma (the central atmosphere immediately surrounding the nucleus) and the tail (a typically linear section consisting of dust or gas blown out from the coma by the Sun's light pressure or out-streaming solar wind plasma).

　　Periodic comets or short-period comets are generally defined as having orbital periods of less than 200 years. They usually orbit more-or-less in the ecliptic plane in the same direction as the planets. Their orbits typically take them out to the region of the outer planets. Long-period comets have highly eccentric orbits and periods ranging from 200 years to thousands of years. An eccentricity greater than 1 when near perihelion does not necessarily mean that a comet will leave the Solar System. The future orbit of a long-period comet is properly obtained when the osculating orbit is computed at an epoch after leaving the planetary region and is calculated with respect to the center of mass of the Solar System.

　　Comets have been observed and recorded since ancient times by many different cultures. Comets had been recorded nearly thirty times in ancient Chinese history. Till 1750, scientists realized that these comets were actually the same one-Halley comet.

　　③Agricultural history of the United States

　　Corn, turkeys, tomatoes, potatoes, peanuts, and sunflower seeds constitute some of the major holdovers from the agricultural endowment of the Americas.

　　European agricultural practices greatly affected the New England landscape, leaving behind many physical foot prints. Colonists brought livestock over from Europe which caused many changes to the land. Grazing animals required a lot of land and food to sustain them and due to grazing, native grasses were destroyed and European species began to replace them. New species of weeds were introduced and began to thrive as they were capable of withstanding the grazing of animals, whereas native species could not. The soil in the middle area was relative fertile, which offered prosperous food supply and exported to other country and traded into North area.

　　In North area, the poorest and richest people are not many, but the poverty gap had increased, since the privatization of land. The lands owned by farmers were quite limited, and this pushed farmers to reduce their non-farming period. This decision made the soil there more barren, due to the over-used farming. Without enough food, many male labor chose to leave and found another place to live. After some time, these farmers who moved had a lot of rest time, which pushed them to take part in a lot of vocation. Their contribution offered other industries development and made the United States prosperous and strong.