Even plant can run a fever, especially when they’re under attack by insects or disease. But unlike human, plants can have their temperature taken from 3, 000 feet away - straight up. A decade ago, adopting 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 - coded map showing where plants were running“ fevers”. Farmers could then spot - spray, using 50 to 70 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. “This technique can be used on 75 percent of agricultural land in the United States, ” says George Oerther of Texas A & M. Ray Jackson , who recently retired from the Department of Agriculture, thinks remote infrared crop scanning could be adopted by the end of the decade. But only ff Paley finds the financial backing which he failed to obtain 10 years ago.

　56．Plants will emit an increased amount of heat when they are________.

　　A. sprayed with pesticides     B. facing an infrared scanner

　　C. in poor physical condition   D. exposed to excessive sun rays

　57．In order to apply pesticide spraying precisely, we can use infrared scanning to________.

　　A. estimate the damage to the crops    B. measure the size of the affected area

　　C. draw a color -coded map          D. locate the problem area

　58．Farmers can save a considerable amount of pesticide by________.

　　A. resorting to spot – spraying   B. consulting infrared scanning experts

　　C. transforming poisoned rain    D. detecting crop problems at an early stage

　59．The application of infrared scanning technology to agriculture met with some difficulties________.,

　　A. the lack of official support        B. its high cost

　　C. the lack of financial support      D. its failure to help increase production

　60．Infrared scanning technology may be brought back into operation because of________.

　　A. the desire of farmers to improve the quality of their produce

　　B. growing concern about the excessive use of pesticides on crops

　　C. the forceful promotion by the Department of Agriculture

　　D. full support from agricultural experts

 

　　Trees are useful to man in three very important ways: they provide him with wood and other products, they give him shade, and they help to prevent drought and floods.

　　Unfortunately, in many parts of the world man has not realized that the third of these services is the most important. In his eagerness to draw quick profit from the trees, he has cut them down in large numbers, only to find that without them he has lost the best friends he had.

　　Two thousand years ago a rich and powerful country cut down its trees to build warships, with which to gain itself an empire. It gained the empire but, without its trees, its soil became hard and poor. When the empire fell to pieces, the country found itself faced by floods and starvation.

　　Even though a government realizes the importance of a plentiful supply of trees, it is difficult for it to persuade the villager to see this. The villager wants wood to cook his food with, and he can earn money by making charcoal or selling wood to the townsman. He is usually too lazy or too careless to plant and look after trees. So unless the government has a good system of control, or can educate the people, the forests will slowly disappear.

　　This does not only mean that the villagers? sons and grandsons have fewer trees. The results are even more serious. For where there are trees their roots break the soil up—allowing the rain to sink in and also hold the soil, thus preventing it being washed away easily, but where there are no trees, the soil becomes hard and poor. The rain falls on hard ground and flows away on the surface, causing floods and carrying away with it the rich topsoil, in which crops grow so well. When all the topsoil is gone, nothing remains but a worthless desert.

63. The purpose that the writer wrote this article for is ____ .

　A. to tell people that trees are very useful to man

　B. to warn people not to cut down trees any more

　C. to warn that man mustn't destroy forests any more

　D. to explain how trees help to prevent drought and floods

64. In the writer's opinion, ____ , or the forests slowly disappear.

　A. measure must be taken                      B. people shouldn't draw benefit from the tree

　C. government must realize the serious results      D. unless trees never be cut down

65. According to the article we know it is ____ to prevent the forests from slowly disappearing.

　A. necessary but impossible                    B. necessary but difficult

　C. impossible and unimportant                  D. difficult and impossible

66. In the last two paragraphs the writer wanted to make it clear that ____ .

　A. where there are no trees, the soil becomes hard and poor

　B. where there are many trees, there are fewer floods

　C. where there are no trees, the land might become desert slowly

　D. floods will make the land become desert

　　Trees are useful to man in three important ways, and they provide 1 with 2 and other products, they give him shade, and they help to prevent drought 3 floods.

　　Unfortunately, in many parts of the world, man has not 4 that the third of these is the most important. In his eagerness to 5 money from trees, he has cut them down in large 6 , only to find that without them he has lost the best 7 he had. And besides, he is usually too 8 to plant and look after new trees. 9 the forests slowly disappear.

　　This does not only 10 that man will have fewer trees. The results are even 11 , for where there are trees, 12 break up soilallowing the rain to sink in and also bind (固定) the soil, thus preventing it from 13 easily; but where there are no trees, the 14 falls on hard ground and flows away, causing floods and carrying away the 15 top-soil. When all the top-soil is gone, nothing remains but worthless desert.

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　　Trees are useful to man in three very important ways: they provide him with wood and other products, they give him shade, and they help to prevent drought and floods.

　　Unfortunately, in many parts of the world man has not realized that the third of these services is the most important. In his eagerness to draw quick profit from the trees, he has cut them down in large numbers, only to find that without them he has lost the best friends he had.

　　Two thousand years ago a rich and powerful country cut down its trees to build warships, with which to gain itself an empire. It gained the empire but, without its trees, its soil became hard and poor. When the empire fell to pieces, the country found itself faced by floods and starvation.

　　Even though a government realizes the importance of a plentiful supply of trees, it is difficult for it to persuade the villager to see this. The villager wants wood to cook his food with, and he can earn money by making charcoal or selling wood to the townsman. He is usually too lazy or too careless to plant and look after trees. So unless the government has a good system of control, or can educate the people, the forests will slowly disappear.

　　This does not only mean that the villagers? sons and grandsons have fewer trees. The results are even more serious. For where there are trees their roots break the soil up—allowing the rain to sink in and also hold the soil, thus preventing it being washed away easily, but where there are no trees, the soil becomes hard and poor. The rain falls on hard ground and flows away on the surface, causing floods and carrying away with it the rich topsoil, in which crops grow so well. When all the topsoil is gone, nothing remains but a worthless desert.

63. The purpose that the writer wrote this article for is ____ .

　A. to tell people that trees are very useful to man

　B. to warn people not to cut down trees any more

　C. to warn that man mustn't destroy forests any more

　D. to explain how trees help to prevent drought and floods

64. In the writer's opinion, ____ , or the forests slowly disappear.

　A. measure must be taken                      B. people shouldn't draw benefit from the tree

　C. government must realize the serious results      D. unless trees never be cut down

65. According to the article we know it is ____ to prevent the forests from slowly disappearing.

　A. necessary but impossible                    B. necessary but difficult

　C. impossible and unimportant                  D. difficult and impossible

66. In the last two paragraphs the writer wanted to make it clear that ____ .

　A. where there are no trees, the soil becomes hard and poor

　B. where there are many trees, there are fewer floods

　C. where there are no trees, the land might become desert slowly

　D. floods will make the land become desert