14 Farmer ED Rawlings smiles as he looks at his orange trees. The young oranges are growing well in Florida’s weather. Warm sunshine and gentle rains, along with ED Rawlings expert care, will produce a good crop of oranges this year.
But ED has to fight against Florida’s changeable winter weather. In January and February, temperature can destroy ED’s entire orange crops. Having farmed in Florida for the past 35 years, Ed Rawlings is prepared for the frosts. When temperatures drop below freezing, Ed tries to save his crop by watering his orange trees. The water freezes and forms a thin layer of ice on the trees. Strange as it may sound, this thin layer of ice actually keep the fruit warm..
What happens is simple. When the trees are watered, the water loses heat and becomes ice. The warmth of the heat it loses is sicked in by the fruit and keeps its temperature at a safe level. Ed Rawling has effectively used this method to save many orange crops.
But Ed still faces some difficulties. The trees should be watered at the exact moment the temperature drops to the freezing point. Also, just the right quantity of water must be used. Too much water can form a thick layer of ice that will break the trees branches. Another difficulty is that wind blows away the heat. So Ed has to worry about not only when but also how often his trees should be watered, and how much water should be used.
Computer technology may help Ed with some of these worries. With equipment, air and soil temperatures and wind speed can be measured. The information is fed into a computer which can tell when temperatures drop to freezing. The computer can correctly decide the quantity of water to be used and how frequently the trees should be watered. Ed will find looking after his orange trees a lot easier with the help of a computer, and we’ll all have the benefits(or advantages) of computerage oranges.
The passage is mainly about_______.
A a farmer’s expert care for his orange trees
B the different uses of computers
C growing oranges in Florida’s changeable weather
D different way of frost protection
15 RALOALTO, California—“Switching off the television may help prevent children from getting fatter—even if they do not change their diet or increase the amount they exercise,” US researchers said last week.
A study of 192 third and forth grades, generally aged eight and nine, found that children who cut the number of hours spent watching television gained nearly two pounds (0.91kg) less over a one-year period than those who did not change their television diet.
“The findings are important because they show that weight loss can only be the result of a reduction in television view and not any other activity,” said Thomas Robison, a pediatrician at Stanford University.
In the study, presented this week to the Pediatric Academic Societies’ annual meeting in San Francisco, the researchers persuaded about 100 of the students to reduce their television viewing by one-quarter to one third.
Children watching fewer hours of television showed a pretty smaller increase in waist size and had less body fat than other students who continued their took part in any extra exercise.
“One explanation for the weight loss could be the children unstuck to the television may simply have been moving around more and burning off calories,” Robinson said.
“Another reason might be due to eating fewer meals in front of the television. Some studies have suggested that eating in front of the TV encourages people to eat more,” Robison said.
The author tried to tell us in the first two paragraphs that _____
A children will get fatter if they eat too much
B Children will get thinner if they eat less
C children will get fatter if they spend less time watching TV
D children will get fatter if they spend more time watching TV
参考答案
主旨题实战演练
1. A 2. A 3. A.A 4. B 5. B. 6. D 7. A
8. B 9. A 10. C 11. A 12. C 13. A 14. A.
15. D
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