题目内容
weather. Warm sunshine and gentle rains, along with Ed Rawlings' expert care, they will produce a good crop
of' oranges this year.
But Ed has to fight against Florida's changeable winter weather. In January and February, temperatures can
destroy Ed's entire orange crop. 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
keeps 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 sucked in by the fruit and keeps its temperature at a safe level. Ed Rawlings 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 Rawlings 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 Rawlings will find looking after his orange trees a lot easier with the
help of a computer, and we'll all have the benefits of computer-age oranges.
B. the different uses of computers
C. growing oranges in Florida's changeable weather
D. different ways of crop protection
B. equipping them with a computer
C. watering them at the proper time
D. picking his fruit at the first sign of frost
B. can be a valuable tool for the farmer
C. can be used to help oranges grow bigger
D. cannot take the place of the farmer's experience and judgement
point.
B. He should decide the exact moment when the orange trees should be watered.
C. He has to water the orange trees more often in January and February.
D. He has to judge how often he should water the orange trees.
B. help the farmer get a better harvest
C. tell the farmer why outdoor temperature changes
D. prevent the temperature from dropping to the freezing point
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