答案：C
根据以下内容，回答下面试题。
Passage Four
Man's first real invention, and one of the most important inventions in history, was the wheel. All transportation and every machine in the world depend on it. The wheel is the simplest yet perhaps the most remarkable of all inventions, because there are no wheels in nature-no living thing was ever created with wheels. How, then, did man come to invent the wheel? Perhaps some early hunters found that they could roll the carcass of a heavy animal through the forest on logs more easily than they could carry it. However, the logs themselves weighed a lot.
It must have taken a great prehistoric thinker to imagine two thin slices of log connected, at their centers by a string stick. This would roll along just as the logs did, yet be much lighter and easier to handle. Thus the wheel and axle came into being and with them the first carts.
第48题 The wheel is important because__________.
A.it was man's first real invention B.all transportation depends on it
C.every machine depends on it D.both B and C
答案：D
第49题 The wheel is called__________.
A.simple B.complicated C.strange D.unusual
答案：D
第50题 It was remarkable of man to invent the wheel because__________.
A.it led to .many other inventions B.man had no use for it then C.there were no wheels in nature
D.all of the above
答案：D
第51题 The wheel was probably invented by__________.
A.a group of early hunters B.the first men on earth C.a great prehistoric thinker D.the man who made the first cart
答案：A
根据以下内容，回答下面试题。
Passage Five
Even plants can run a fever, especially when they're under attack by insects or disease. But unlike humans, plants can have their temperature taken from 3,000 feet away--straight up. A decade ago, adapting the infrared (红外线) scanning technology developed for military purposes and other satellites, physicist Stephen Paley came up with a quick way to take the temperature of crops to determine which ones are under stress.
The goal was to let farmers precisely target pesticide (杀虫剂) spraying rather than rain poison on a whole field, which invariably includes plants that don't have pest (害虫) problems.
Even better, Paley's Remote Scanning Services Company could detect crop problems before they became visible to the eye. Mounted on a plane flown at 3,000 feet at night, an infrared scanner measured the heat emitted by crops. The data were transformed into a color-code map showing where plants were running\spot-spray, using 50 to70 percent less pesticide than they otherwise would.
The bad news is that Paley's company closed down in 1984, after only three years. Farmers resisted the new technology and long-term backers were hard to find. But with the renewed concern about pesticides on produce, and refinements in infrared scanning, Paley hopes to get back into operation. Agriculture experts have no doubt the technology works~ \United States\recently retired from the Department of Agricultrue, thinks re- mote infrared crop scanning could be adopted by the end of the decade. But only if Paley finds the financial backing which he failed to obtain 10 years ago.
第52题 In order to apply pesticide spraying precisely, we can use infrared scanning to__________. A.locate the problem areas B.drew a color-ceded map
C.measure the size of the affected area D.estimate the damage to the crops
答案：A
第53题 Farmers can save a considerable amount of pesticide by__________.
A.transforming poisoned rain B.consulting infrared scanning experts C.resorting to spot-spraying D.detecting crop problems at an early date
答案：C
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