题目

第三部分：阅读理解（共20小题，满分40分） 第一节：阅读下列三篇短文，从每题所给的四个选项(A、B、C和D)中，选出最佳选项，并在答题卡上将该项涂黑。（共15小题，满分30分） Frank Woolworth was born in Rodman, New York., in 1852. His family were very poor farmers, and there was never enough to eat. Frank decided he did not want to be farmer. He took a short business course, and went to work as a salesman in a large city. Woolworth realized he had a natural skill for showing goods to attract people’s interest, but he soon learned水体污染是指大量的污染物排入水体，水体及周围的生态平衡遭到破坏．水体污染的主要来源有工业污染、 、 ．自然界的水往往含有一些杂质，需要运用适当的方法净水．以下是一些实验室常用的净水方法：①利用活性炭吸附 ②采用静置沉淀 ③过滤 ④蒸馏 ⑤投药消毒，请选取合适的序号完成下述填空．上述方法中，只能除去不溶性杂质的是 、只能除去有机色素或异味的是 、能除去大多数杂质，并使硬水软化的是 、上述方法中属于化学变化的是 ．