1、托福（阅读）模拟试卷 1及答案与解析 一、 Sections Three： Reading Comprehension 0 “Producers, Consumers, and Decomposers“ P1 Organisms that are capable of using carbon dioxide as their sole source of carbon are called autotrophs (self-feeders), or producers. These are the plants. They chemically fix carbon through phot
2、osynthesis. Organisms that depend on producers as their carbon source are called heterotrophs (feed on others), or consumers. Generally, these are animals. From the producers, which manufacture their own food, energy flows through the system along a circuit called the food chain, reaching consumers
3、and eventually detritivores. Organisms that share the same basic foods are said to be at the same trophic level. Ecosystems generally are structured in a food web, a complex network of interconnected food chains. In a food web, consumers participate in several different food chains, comprising both
4、strong interactions and weak interactions between species in the food web. P2 Primary consumers feed on producers. A Because producers are always plants, the primary consumer is called an herbivore, or plant eater. A carnivore is a secondary consumer and primarily eats meat. B A consumer that feeds
5、on both producers (plants) and consumers (meat) is called an omnivore. C P3 Detritivores (detritus feeders and decomposers) are the final link in the endless chain. D Detritivores renew the entire system by releasing simple inorganic compounds and nutrients with the breaking down of organic material
6、s. Detritus refers to all the dead organic debris remains, fallen leaves, and wastes that living processes leave. Detritus feeders worms, mites, termites, centipedes, snails, crabs, and even vultures, among others work like an army to consume detritus and excrete nutrients that fuel an ecosystem. De
7、composers are primarily bacteria and fungi that digest organic debris outside their bodies and absorb and release nutrients in the process. This metabolic work of microbial decomposers produces the rotting that breaks down detritus. Detritus feeders and decomposers, although different in operation,
8、have a similar function in an ecosystem. P4 An example of a complex community is the oceanic food web that includes krill, a primary consumer. Krill is a shrimplike crustacean that is a major food for an interrelated group of organisms, including whales, fish, seabirds, seals, and squid in the Antar
9、ctic region. All of these organisms participate in numerous other food chains as well, some consuming and some being consumed. Phytoplankton begin this chain by harvesting solar energy in photosynthesis. Herbivorous zoo-plankton such as krill and other organisms eat Phytoplankton. Consumers eat kril
10、l at the next trophic level. Because krill are a protein-rich, plentiful food, increasingly factory ships, such as those from Japan and Russia, seek them out. The annual krill harvest currently surpasses a million tons, principally as feed for chickens and livestock and as protein for human consumpt
11、ion. Efficiency in a Food Web P5 Any assessment of world food resources depends on the level of consumer being targeted. Let us use humans as an example. Many people can be fed if wheat is eaten directly. However, if the grain is first fed to cattle (herbivores) and then we eat the beef, the yield o
12、f available food energy is cut by 90% (810 kg of grain is reduced to 82 kg of meat); far fewer people can be fed from the same land area. P6 In terms of energy, only about 10% of the kilocalories (food calories, not heat calories) in plant matter survive from the primary to the secondary trophic lev
13、el. When humans consume meat instead of grain, there is a further loss of biomass and added inefficiency. More energy is lost to the environment at each progressive step in the food chain. You can see that an omnivorous diet such as that of an average North American and European is quite expensive i
14、n terms of biomass and energy. P7 Food web concepts are becoming politicized as world food issues grow more critical. Today, approximately half of the cultivated acreage in the United States and Canada is planted for animal consumption beef and dairy cattle, hogs, chickens, and turkeys. Livestock fe
15、ed includes approximately 80% of the annual corn and nonexported soybean harvest. In addition, some lands cleared of rain forest in Central and South America were converted to pasture to produce beef for export to restaurants, stores, and fast-food outlets in developed countries. Thus, lifestyle dec
16、isions and dietary patterns in North America and Europe are perpetuating inefficient food webs, not to mention the destruction of valuable resources, both here and overseas. Glossary phytoplankton: a plant that lives in the sea and produces its own energy source trophic level: category measured in s
17、teps away from the energy input in an ecosystem 1 According to paragraph 1, which of the following is true about autotrophs? （ A） They use a chemical process to produce their own food. （ B） They require plant matter in order to survive. （ C） They need producers to provide them with carbon. （ D） They
18、 do not interact with other organisms in the food chain. 2 The word sole in the passage is closest in meaning to （ A） major （ B） steady （ C） only （ D） ideal 3 Based on the information in paragraph 1, which of the following best explains the term “food web“? （ A） Energy manufactured by producer organ
19、isms in the food chain （ B） Another term that defines the food chain （ C） An interactive system of food chains （ D） Primary and secondary consumers in the food chain 4 It may be concluded that human beings are omnivores because （ A） people feed on producers for the most part （ B） people are usually
20、tertiary consumers （ C） people generally eat both producers and consumers （ D） most people are the top carnivores in the food chain 5 The word others in the passage refers to （ A） debris （ B） feeders （ C） processes （ D） nutrients 6 Why does the author mention krill in paragraph 4? （ A） To suggest a
21、solution for a problem in the food chain （ B） To provide evidence that contradicts previously stated opinions （ C） To present an explanation for the killing of krill （ D） To give an example of a complex food web 7 Which of the sentences below best expresses the information in the highlighted stateme
22、nt in the passage? The other choices change the meaning or leave out important information. （ A） Part of the one million tons of krill harvested annually is used for protein in animal feed. （ B） Both livestock and chickens as well as humans eat krill as a main part of their diets. （ C） The principal
23、 use of krill is for animal feed, although some of the one million tons is eaten by people. （ D） More than one million tons of krill is eaten by both animals and humans every year. 8 According to paragraph 7, how much land is used to grow crops for animal feed? （ A） 80 percent of the acreage in Euro
24、pe （ B） Most of the rain forest in Central America （ C） 50 percent of the farm land in Canada and the United States （ D） Half of the land in North and South America 9 According to paragraph 7, food webs are inefficient because （ A） consumers in developed nations prefer animal protein （ B） politician
25、s are not paying attention to the issues （ C） there are not enough acres to grow crops efficiently （ D） too much of the corn and soybean harvests are exported 10 Which of the following statements most accurately reflects the authors opinion about food issues? （ A） Too much grain is being exported to
26、 provide food for developed nations. （ B） More forested land needs to be cleared for food production in developing nations. （ C） Food choices in developed nations are very costly in terms of the environment. （ D） More animal protein is needed in the diets of people in developing nations. 11 Look at
27、the four squares that show where the following sentence could be inserted in the passage. A tertiary consumer eats primary and secondary consumers and is referred to as the “top carnivore“ in the food chain. Where could the sentence best be added? Click on a square to insert the sentence in the pass
28、age. 12 According to the passage, all of the following characteristics describe producers EXCEPT （ A） Producers serve as food for consumers. （ B） Producers make their own food. （ C） Producers form the first trophic level. （ D） Producers include bacteria and fungi. 13 Complete the table by matching t
29、he phrases on the left with the headings on the right. Select the appropriate answer choices and drag them to the type of organism to which they relate. TWO of the answer choices will NOT be used. This question is worth 4 points. To delete an answer choice, click on it. To see the passage, click on
30、View Text. Answer Choices A Depend upon photosynthesis to survive B Has a weak interaction among species C Generally consist of animal life forms D Include both herbivores and carnivores E Form the last link in the food chain F Eat meat as one of its primary food sources G Feed on dead plants and an
31、imals H Are always some variety of plant life I Made exclusively of inorganic materials Producers - - Consumers - - - Decomposers - - 14 An introduction for a short summary of the passage appears below. Complete the summary by selecting the THREE answer choices that mention the most important points
32、 in the passage. Some sentences do not belong in the summary because they express ideas that are not included in the passage or are minor points from the passage. This question is worth 2 points. The food web is comprised of producers, consumers, and decomposers, which interact in endless cycles. An
33、swer Choices A Consumers, primarily animals, feed on producers, plants which manufacture their own food source through photosynthesis. B Decomposers digest and recycle dead plants and animals, releasing inorganic compounds into the food chain. C Since more energy is depleted into the environment at
34、each level in the food chain, dietary choices affect the efficiency of food webs. D Among consumers, human beings are considered omnivores because they eat not only plants but also animals. E An example of an undersea food web includes phytoplankton, krill, and fish as well as birds, seals, and whal
35、es. F Rain forests are being cut down in order to clear pastureland for cattle that can be exported to countries with fast-food restaurants. 14 “The Heredity Versus Environment Debate“ P1 The past century has seen heated controversy about whether intelligence, which relates strongly to school achiev
36、ement, is determined primarily by heredity or by environment. A When IQ tests were undergoing rapid development early in the twentieth century, many psychologists believed that intelligence was determined primarily by heredity. B P2 Environmentalist view. By the middle of the twentieth century, nume
37、rous studies had counteracted the hereditarian view, and most social scientists took the position that environment is as important as or even more important than heredity in determining intelligence. C Social scientists who stress the environmentalist view of intelligence generally emphasize the nee
38、d for continual compensatory programs beginning in infancy. Many also criticize the use of IQ tests on the grounds that these tests are culturally biased. D P3 James Flynn, who collected similar data on other countries, found that “massive“ gains in the IQ scores of the population in fourteen nation
39、s have occurred during the twentieth century. These improvements, according to Flynns analysis, largely stemmed not from genetic improvement in the population but from environmental changes that ied to gains in the kinds of skills assessed by IQ tests. Torsten Husen and his colleagues also have conc
40、luded, after reviewing large amounts of data, that improvements in economic and social conditions, and particularly in the availability of schooling, can produce substantial gains in average IQ from one generation to the next. In general, educators committed to improving the performance of low-achie
41、ving students find these studies encouraging. P4 Hereditarian view. The hereditarian view of intelligence underwent a major revival in the 1970s and 1980s, based particularly on the writings of Arthur Jensen, Richard Herrnstein, and a group of researchers conducting the Minnesota Study of Twins. Sum
42、marizing previous research as well as their own studies, these researchers identified heredity as the major factor in determining intelligence accounting for up to 80 percent of the variation in IQ scores. P5 Jensen published a highly controversial study in the Harvard Educational Review in 1969. Po
43、inting out that African-Americans averaged about 15 points below whites on IQ tests, Jensen attributed this gap to a genetic difference between the two races in learning abilities and patterns. Critics countered Jensens arguments by contending that a host of environmental factors that affect IQ, inc
44、luding malnutrition and prenatal care are difficult to measure and impossible to separate from hereditary factors. IQ tests are biased, they said, and do not necessarily even measure intelligence. After his 1969 article, Jensen has continued to cite data that he believed link intelligence primarily
45、to heredity. His critics continue to respond with evidence that environmental factors, and schooling in particular, have a major influence on IQ. P6 Synthesizers view. Certain social scientists have taken a middle, or “synthesizing,“ position in this controversy. The synthesizers view of intelligenc
46、e holds that both heredity and environment contribute to differences in measured intelligence. For example, Christopher Jencks, after reviewing a large amount of data, concluded that heredity is responsible for 45 percent of the IQ variance, environment accounts for 35 percent, and interaction betwe
47、en the two (“interaction“ meaning that particular abilities thrive or wither in specific environments) accounts for 20 percent. Robert Nichols reviewed all these and other data and concluded that the true value for heredity may be anywhere between 0.40 and 0.80 but that the exact value has little im
48、portance for policy. In general, Nichols and other synthesizers maintain that heredity determines the fixed limits of a range; within those limits, the interaction between environment and heredity yields the individuals intelligence. In this view, even if interactions between heredity and environmen
49、t limit our ability to specify exactly how much of a childs intelligence reflects environmental factors, teachers (and parents) should provide each child with a productive environment in which to realize her or his maximum potential. Glossary IQ: intelligence quotient; a numerical value for intelligence 15 According to paragraph 2, which of the following is true about environmentalists? （ A） They had only a few studies to prove their viewpoint. （ B） They did not agree with the use of IQ tests to measure intelligence. （ C） Th
