二次元学姐farmer was Ed Rawlings.
But Ed has to fight against Florida’s changeable winter. 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(冰点), Ed tries to save his crops by watering his orange trees. The water freezes and forms a thin layer(层) of ice on the trees. Strange as it may sound, this layer of ice actually keeps the fruit warm.
What happens is simple. When the trees are watered, the water loses heat and 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 have the benefits of computer-age oranges.
31. What is the passage 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 ways of frost protection.
32. Ed tried to protect and save his crop by .
