单选题
Scientists have devised ways to collect solar energy in one area of a building and carry it to another area. Solar collectors collect and change solar energy into heat energy. These devices are positioned on a building in a
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that allows for maximum exposure to sunlight. Some can
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be moved or tilted to follow the sun. Many collectors are flat metal plates painted black. They are painted black because a dark surface absorbs solar energy better than a
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one. Water or air passing in pipes
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the plates is heated. The warm water or air is then pumped to places
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it is needed. The same water or air can be used over and over to absorb and transport heat.
Solar cells are used to collect solar energy and
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it into electric energy. These devices are used on space flights. Large panels covered with thousands of solar cells provide electric power for the spacecraft. On Earth, solar cells are in use in homes and businesses.
Buildings using solar cells or solar collectors or
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exist today. It is probable that more will be built in the future. However, the conversion of already existing buildings to solar energy is not realistic in most
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due to the
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involved. Also, most existing buildings are not located or positioned for maximum exposure to sunlight.
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, the use of solar energy to
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the energy needs of a single building is growing.
What about using solar energy on a large scale to provide electricity, not just for a
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home, but for a whole
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? The problem here is that the sun"s energy,
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plentiful, is spread out over an enormous area. Suppose solar cells were being used to produce as much electricity as the
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currently being produced in the United States by other
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. Experts estimate that this
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require solar cells covering from 25000 to 70000 square kilometers of land!
As the use of solar energy grows and is
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investigated, more practical and effective applications of it will be developed. Although it does not seem to have a negative effect on the environment, there is a possibility that the widespread use of solar energy might
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some change in the overall distribution of heat from the sun. However, at the present time, solar energy does appear to be a promising energy alternative. People should also
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that once they have paid the price for the purchase and installation of solar energy devices, the sunlight is free.
【答案解析】[解析] 此处要表达的意思是把太阳能转换成电能，而且在四个选项中能与后面的介词into连用的只有change。A)调整……以适应……(adjust…to…)；B)改变，转变……成为……(change…into…)；C)变换思路、话题等，转移(switch from…to…)，例如：He is always switching from one job to another；D)from是介词，不能做谓语。故答案是B)。
【答案解析】[解析] 短文中提供了介词by，只有means与by搭配，构成介词短语by other means，表示“通过其他方式或手段”，因此，答案是B)。A)方法，习惯，态度，指行为举止的方式，常与介词in连用，如：advance in the same manner(以同样方式前进)；C)方法，办法，表示做某事的具体步骤或程序，强调效率、准确；D)常与介词in连用，表示以……方式、手段。