2. 外语
  3. Space is filled with radiant energy and beyond earth’s atmosphere this energy flow steadily and intensely from the sun. An abund

Space is filled with radiant energy and beyond earth’s atmosphere this energy flow steadily and intensely from the sun. An abund

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问题     Space is filled with radiant energy and beyond earth’s atmosphere this energy flow steadily and intensely from the sun. An abundant and essential【C1】______of energy would be used in space by developing satellite solar【C2】______stations. To live in space, humans must be protected【C3】______the fierce intensity and penetrating sunlight. The colony will have to have enough energy to【C4】______a fairly uniform temperature. The sun is not dimmed【C5】______an atmosphere. Shaded materials not【C6】______to direct sunlight will almost be absolute zero, while the temperature can soar above the【C7】______point. The colony will need to have both heaters and【C8】______Fortunately, sun’s energy can be converted【C9】______electricity.  Converting sun’s energy, we would【C10】______stations in the space that would intercept【C11】______sunlight. The stations intercept enough sunlight to【C12】______five nuclear reactors and they could be as【C13】______as nine miles long and four miles wide while they weigh twenty thousand tons. This is a【C14】______free way to generate electricity and cost no【C15】______than coal or nuclear energy. Solar cells do the actual converting. A useful material found in lunar soil is silicon which is used to make solar cells.【C16】______we can produce a large amount of these cells and then we avoid any problems of【C17】______the material from earth. A solar cell is made from two thin layers of silicon. Sunlight【C18】______on the cell shakes the electrons【C19】______, and then these electrons move off into an outside circuit, which is detected as an electrical current. Things are arranged【C20】______most of the work involved in generating the electricity is done by forces associated with the atoms themselves.
【C14】
选项 A、sewage
B、expense
C、gasoline
D、pollution
答案D
解析 名词辨析题。利用太阳为能源是没有污染的发电途径，pollution free的意思是“没有污染”，所以应该选D。sewage“污水”；expense“费用”；gasoline“汽油”，这几个词不符合句意，故排除。
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大学英语四级

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