1、托福-练习一及答案解析(总分：39.00，做题时间：90 分钟)一、Passage 1(总题数：2，分数：13.00)North American GrasslandsIn North America, native grasslands occur primarily in the Great Plains in the middle of the continent. The North American prairie biome is one of the most extensive grasslands in the world, extending from the edge o
2、f the Rocky Mountains in the west to the deciduous forest in the east, and from northern Mexico in the south to Canada in the north. Average annual rainfall ranges from about 40 cm (16 inches) in the west to 80 cm (31 inches) in the east. Average annual temperatures range between 10 degrees and 20 d
3、egrees Celsius (50 to 68 degrees Fahrenheit). In the moist regions of the North American grasslands, especially in the northern Great Plains, rainfall is distinctly seasonal, and temperatures can vary widely from very hot in summer to bitter cold in winter.One hundred years ago, the Great Plains gra
4、sslands were one vast, unbroken prairie. Much of the prairie is now farmland, the most productive agricultural region in the world, dominated by monocultures of cereal grains. Wheat, barley, soybeans, corn, and sunflowers occupy the land that was once prairie. In areas given over to grazing lands fo
5、r cattle and sheep, virtually all the major native grasses have been replaced by alien species. （分数：12.00）(1).All of the following statements are true of the northern Great Plains EXCEPT _.A. Summer temperatures are very hot, while winter temperatures are very coldB. An unbroken prairie now extends
6、from the western mountains to the eastern forestC. The original vegetation consisted of shortgrass, mixed grass, and tallgrassD. A large number of small wetlands are found throughout the region（分数：1.00）A.B.C.D.(2).What has taken place in the Great Plains grasslands during the last century?A. The ave
7、rage annual rainfall has risen and fallen several times.B. Large parts of the prairie have been converted to agricultural use.C. Melting glaciers have formed numerous depressions in the soil.D. Scientists have transformed the region into one large carbon sink.（分数：1.00）A.B.C.D.(3).The word “alien“ in
8、 paragraph 2 is closest in meaning to _.A. healthy B. simple C. cheaper D. imported（分数：1.00）A.B.C.D.(4).The prairie potholes owe their origins mainly to _.A. the variation in temperature throughout the yearB. the glaciers that melted at the end of the last Ice AgeC. the heavy rains that fall in the
9、spring and summerD. the increase in greenhouse gases in the atmosphere（分数：1.00）A.B.C.D.(5).Which sentence below best expresses the essential information in the highlighted sentence in paragraph 4? Incorrect choices change the meaning in important ways or leave out essential information.A. The wetlan
10、ds completely cover the landscape, making it difficult to grow crops and grass for grazing.B. The native grasses that grew in the potholes have been replaced with crops that are more beneficial.C. Except for the potholes region, the entire prairie has been converted to cropland and grazing land.D. E
11、ven though a large portion of the prairies is used for crops and grazing, the small ponds remain.（分数：1.00）A.B.C.D.(6).The word “dot“ in paragraph 4 is closest in meaning to _.A. cover B. drain C. warm D. damage（分数：1.00）A.B.C.D.(7).Why does the author use the term “duck factory“ in paragraph 4?A. To
12、point out that ducks are the regions main product for export.B. To emphasize the areas value as a breeding ground for ducks.C. To illustrate the tremendous growth of the poultry industry.D. To show that the potholes are important to the regions economy.（分数：1.00）A.B.C.D.(8).What is the function of a
13、carbon sink?A. It regulates carbon emissions from human activities.B. It measures the amount of carbon dioxide in the ecosystem.C. It collects and drains seasonal rainwater from the soil.D. It removes carbon dioxide naturally from the atmosphere.（分数：1.00）A.B.C.D.(9).The word “this“ in paragraph 5 re
14、fers to _.A. the emission of carbon dioxide from cars, factories, and power plantsB. the action of carbon dioxide as a greenhouse gasC. the capture and storage of carbon dioxide in trees, soil, and plantsD. the average amount of carbon dioxide in one acre of land（分数：1.00）A.B.C.D.(10).What can be inf
15、erred from paragraph 5 about carbon sequestration in the prairie pothole region?A. It depends on the land not being disturbed by agriculture.B. It creates a beneficial habitat for many species of birds.C. It is a leading cause of the warming of the atmosphere.D. It exceeds the amount of carbon captu
16、red anywhere else.（分数：1.00）A.B.C.D.(11).The word “offset“ in paragraph 5 is closest in meaning to _.A. preserve B. transform C. counteract D. measure（分数：1.00）A.B.C.D.(12).Look at the four squares, , , and （分数：1.00）A.B.C.D.1.Read the first sentence of a summary of the passage. Complete the summary by
17、 selecting the THREE answer choices that express the most important ideas in the passage. Some sentences do not belong in the summary because they express ideas that are not presented in the passage or are minor ideas in the passage. This question is worth 2 points.The grasslands of North America co
18、nsist mainly of the prairies in the Great Plains._Answer ChoicesA. Grasslands are found in the intermediate zone between dry desert and moist forest habitats.B. Most of the native prairie grasses have been replaced with cereal crops and grasses for grazing.C. Millions of glacial potholes that functi
19、on as seasonal wetlands are an important feature of the region.D. Waterfowl such as northern pintails, mallards, coots, and pied-billed grebes live in the northern Great Plains.E. The prairie potholes have environmental value as a breeding ground for birds and as a potential carbon sink.F. Storing 4
20、00 million tons of carbon is the equivalent of removing 4 million cars from the road.（分数：1.00）填空项 1:_二、Passage 2(总题数：1，分数：13.00)Air BagAn air bag is an inflatable cushion designed to protect automobile occupants from serious injury in the case of a collision. The air bag is part of an inflatable res
21、traint system, also known as an air cushion restraint system (ACRS) or an air bag supplemental restraint system (SRS), because the air bag is designed to supplement the protection offered by seat belts. Seat belts are still needed to hold the occupant securely in place, especially in side impacts, r
22、ear impacts, and rollovers. Upon detecting a collision, air bags inflate instantly to cushion the exposed occupant with a big gas-filled pillow.A typical air bag system consists of an air bag module, crash sensors, a diagnostic monitoring unit, a steering wheel connecting coil, and an indicator lamp
23、. These components are all interconnected by a wiring harness and powered by the vehicles battery. Air bag systems hold a reserve charge after the ignition has been turned off or after the battery has been disconnected. Since components vital to the systems operation might sit dormant for years, the
24、 air bag circuitry performs an internal “self-test“ during each startup, usually indicated by a light on the instrument panel that glows briefly at each startup. （分数：13.00）(1).According to the passage, an air bag is _.A. a restraint system to supplement the protection offered by a seat beltB. more e
25、ffective than a seat belt in preventing most injuriesC. designed to detect and prevent a collisionD. inflatable and can hold the occupant in place the moment it detects a collision（分数：1.00）A.B.C.D.(2).According to the passage, a reserve charge is necessary when _.A. the power is turned offB. the bac
26、kup power has run outC. the battery needs to be connected againD. the power needs to be reserved for future use（分数：1.00）A.B.C.D.(3).Look at the four squares, , , , and （分数：1.00）A.B.C.D.(4).In the passage, the word “dormant“ is closest in meaning to _.A. potential B. dominating C. useless D. inactive
27、（分数：1.00）A.B.C.D.(5).What can be inferred from the information in paragraph 3 about the early air bags?A. They produced poisonous gases when heated up.B. They were recognized as inventions in the 1950s.C. They were filled with phosgene gas.D. They were filled with poisonous gases.（分数：1.00）A.B.C.D.(6
28、).In the passage, the word “bulky“ is closest in meaning to _.A. clumsy B. compressed C. hazardous D. tight（分数：1.00）A.B.C.D.(7).The air bags designed by John Hetrick had all of the following features EXCEPT _.A. A button could automatically send air into the air bag in the case of a collisionB. John
29、 Hetrick once experienced an accidentC. Many other inventors and researchers applied his design to their own useD. The air bags were installed at four different positions to protect the driver（分数：1.00）A.B.C.D.(8).Which of the following sentences best expresses the essential information in the senten
30、ce below? Incorrect answer choices omit important information or change the meaning of the original sentence in an important way.Many other inventors and researchers followed suit, all exploring slightly different designs, so that the exact technical trail from the early designs to the present syste
31、m is impossible to note with certainty.A. Many inventors and researchers improved John Hetricks air bag and it is now impossible to tell who the real designer of the present system is.B. The technical problem which troubled all designers is that the designs were too similar to be distinguished from
32、one another.C. Many inventors and researchers were also awarded patents for their designs, but it is not certain how many air bag systems were invented.D. Different air bags were invented after John Hetrick was awarded a patent, but it is hard to tell the technical improvement in this process.（分数：1.
33、00）A.B.C.D.(9).The word “it“ in paragraph 5 refers to _.A. a solid propellant B. NaN3C. a metallic oxide D. sodium azide in its solid state（分数：1.00）A.B.C.D.(10).Which of the following is closest in meaning to the word “fatalities“ in paragraph 5?A. Misfortunes. B. Injuries.C. Deaths. D. Accidents.（分
34、数：1.00）A.B.C.D.(11).The author cites the two studies in paragraph 5 in order to _.A. demonstrate that the combination of safety belts and air bags is more effective and reliable than air-bags aloneB. suggest that controlled tests should be conducted on all air bag-equipped cars to ensure effectivene
35、ss and reliabilityC. provide evidence that air bag-equipped cars are effective and reliable in preventing drive fatalities since the 1960sD. strengthen the claim that air bags are the most effective way to prevent drive fatalities in frontal collisions（分数：1.00）A.B.C.D.(12).According to the passage,
36、by which year should all vans be equipped with air bags?A. 1990. B. 1991. C. 1998. D. 1999.（分数：1.00）A.B.C.D.(13).Directions. Below is an introductory sentence for a brief summary of the passage. Complete the summary by writing the letters of THREE of the answer choices that express the most importan
37、t ideas of the passage. Some of the answer choices are incorrect because they express ideas thatare not given in the passage or because they express only details from the passage. This question is worth 2 points.The present-day air bag contains several components to guarantee its effectiveness and r
38、eliability._Answer ChoicesA. Regulations and laws have been passed to ensure that automobiles install air bags.B. Data show that air bag-equipped cars are effective and reliable in reducing driver fatalities.C. Notable technical improvement can be traced from the early designs to the present system.
39、D. Several pioneers have contributed to the effectiveness and reliability of air bags.E. Early air bags were large and might produce poisonous gas.（分数：1.00）填空项 1:_三、Passage 3(总题数：1，分数：13.00)Film Exchanges in Americas Early Movie IndustryMotion pictures were exhibited to the public in the late 1800s,
40、 though the first device to accomplish this would seem very unfamiliar to todays movie-going audiences. Thomas Edisons 1893 Kinetoscope was little more than a wooden box with a small glass window. Intended only for individual viewing, it housed a roll of film, a mechanical device to circulate the fi
41、lm, and a small light to illuminate it. A person would peer through the window and watch a short moving sequence, usually just a depiction of an everydayevent or the performance of an acrobat or dancer. Needless to say, the mediums ability to serve only one customer at a time severely limited its pr
42、ofitability.Everything changed two years later with the advent of projection, by which a much larger film image could be shown to multiple viewers simultaneously. The Lumiere brothers of France were the first to introduce this new technology with a projection machine called a cinematograph. Edison w
43、as quick to follow their lead and created his Vitascope projector in late 1895. With the potential to make money by charging admission to movies now within reach, the innovators of the film industry were ready to expand their business ventures.There were two industry models in practice during the ea
44、rly 1900s. A handful of successful firms, such as the Biograph Company, owned the equipment to make their own films as well as the venues in which to display them. Such companies were rare, however; most films were shown by independent exhibitors. These included traditional theater owners, who added
45、 short film presentations to their programs of live-action entertainment, and traveling cinema exhibitors, who moved from town to town to reach new audiences, often following circuits established by rural fairs. They typically purchased films directly from the production companies that made them, pa
46、ying a set price per foot of film regardless of its content. Because movies of the time were never longer than one or two minutes, it was feasible to buy them outright. However, this system failed to attract significant audiences as the public soon tired of the small stock of films exhibitors had to
47、 offer, and the reels of film themselves deteriorated quickly through repeated transport and screening in traveling cinema shows.Things changed again when producers began increasing the length of their films in order to tell more complex stories. Longer films entailed higher prices, and it became di
48、fficult for small-scale exhibitors to purchase them. This, in turn, prevented production studios from creating as many movies as they could, since they had no one to sell them to. It was precisely this dilemma that gave rise to the film exchange. An early version of a motion-picture distributor, fil
49、m exchanges were responsible for bridging the gap between production and exhibition. They financed production studios, giving them the funds they needed to film more movies. Then, they purchased these films and rented them out to exhibitors around the country for a fraction of what it would have cost the exhibitors to purchase the films themselves.The film-exchange system revolutionized the industry, greatly benefiting all parties involved. Film
