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【专家解说】：【答案】
【小题1】C
【小题2】A
【小题3】C
【小题4】B
【答案解析】文章大意：本文是一篇科技说明文。文章介绍了biomass(生物量)的特征、生物量的优点以及它在美国能源中的地位。
【小题1】细节理解题。根据第二段中的“because the energy it contains comes from the sun.When plant matter is burned, it gives off the sun's energy.In this way, biomass serves as a sort of natural battery for storing the sun's energy.”可知C正确。
【小题2】推理判断题。根据第三段中的“In 2008—although the numbers aren't all in yet—wind power probably took over first place because of the rapid development of wind farms across the country.”可知，2008年风能占居首位。关键词定位：A项中的the leader of 和first place为同意表达。
【小题3】推理判断题。根据最后一段中的“Some homeowners also try to make their own heat by using biomass materials.Such practice may save homeowners' money, but it also produces a lot of pollution.So, the best way is to encourage power plants to use it.”可知C正确。
【小题4】推理判断题。根据全文内容可知，本文是一篇有关生物量能源的科普类文章。所以，它应该是科学杂志上的文章。故选B。