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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 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 spraying rather than rain poison on a whole field, which invariably includes plants that don’t have pest 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% 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% 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 If Paley finds the financial backing which he failed to obtain 10 years ago. Farmers can save a considerable amount of pesticide by（）
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Before the 20th century, the horse provided day to day transportation in the United States. Trains were used only for long-distance transportation.Today the car is the most popular sort of transportation in all of the United States. It has completely replaced the horse as a means of everyday transportation. Americans use their car for nearly 90 percent of all personal trips.Most Americans are able to buy cars. The average price of a recently made car was $ 2050 in 1950, $ 2740 in 1960 and up to $ 4750 in 1975. During this period American car manufacturers set about improving their products and work efficiency. As a result, the yearly income of the average family increased from 1950 to 1975 faster than the price of cars. For this reason purchasing a new car takes a smaller part of a family’s total earnings today. What was the average price of a recently made car in 1960（）
America is a country on the move. In unheard of numbers, people of all ages are exercising their way to better health. According to the latest figures, 59 percent of American adults exercise regularly-up 12 percent from just two years ago and more than double the figure of 25 years ago. Even non-exercisers believe they would be more attractive and confident if they were more active.It is hard not to get the message. The virtues of physical fitness are shown on magazine covers, postage stamps, and television ads for everything from beauty soaps to travel books. Exercise as a part of daily life did not catch on until the late 1960s when research by military doctors began to show the health benefits of doing regular physical exercises. Growing publicity (宣传) for races held in American cities helped fuel a strong interest in the ancient sport of running. Although running has leveled off in recent years as Americans have discovered equally rewarding--and sometimes safer-forms of exercise, such as walking and swimming, running remains the most popular form of exercise.As the popularity of exercise continues to mount, so does scientific evidence of its health benefits. The key to fitness is exercising the major muscle groups vigorously (强有力地) enough to approximately double the heart rate and keep it doubled for 20 to 30 minutes at a time. Doing such physical exercises three times or more a week will produce considerable improvements in physical health in about three months. It can be learnt from the passage that the health benefits of exercise（）
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 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 spraying rather than rain poison on a whole field, which invariably includes plants that don’t have pest 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% 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% 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 If Paley finds the financial backing which he failed to obtain 10 years ago. The application of infrared scanning technology to agriculture met with some difficulties due to（）
M: Going to the football game todayW: No, but I’ll be watching it on television with some friends．M: Weren’t you able to get any ticketsW: I didn’t try．I really don’t go to games so often．M: But don’t you enjoy going Don’t you find it exciting to be part of the crowdW: Oh sure，nothing beats the atmosphere at a sporting event: the cheering, all that energy．But sometimes it’s just too inconvenient getting into and out of the stadium before and after the game．And if you watch the game with friends, or at a bar or restaurant…M: …you’ve basically created your own crowd．W: That’s right．Another reason why I like to watch sports on TV is that I simply find it easier to follow the action on TVM: Yeah．sometimes it is a little difficult to keep track of the ball when you’re sitting in the stands．W: Especially when your seats are far from the field．M: It’s like you’re watching from an airplane．sometimes．W: Mso．good sports comments on TV can add to your understanding and enjoyment of the game．M: After listening to you I’m starting to wonder how they are able to sell any tickets to these games． What is the advantage of watching games in the stadium（）
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