Several of the chemical elements were known in prehistoric【C1】______ . One of the great【C2】______ forward in civilization came w

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问题     Several of the chemical elements were known in prehistoric【C1】______ . One of the great【C2】______ forward in civilization came when bronze, an alloy,【C3】______ stone as the main material for tools and weapons. The iron replaced bronze. The first elements【C4】______ were those that were found free in nature or could be readily【C5】______ from their ores at relatively low temperatures. During the Middle Ages, chemistry was mostly practised by the alchemists,【C6】______ tried to turn base metals into gold, and who were interested in discovering a way of living for【C7】______ . But they discovered many important【C8】______ about the metals and some of the most easily attainable compounds. Even before the Middle Ages, people knew how to【C9】______ mercury, tin, and iron from their ores. By the time of Paracelsus, chemistry was developed largely to the effort of【C10】______ medicines.
【C10】

选项 A、retaining
B、containing
C、obtaining
D、sustaining

答案C

解析 A项retaining意为(保存,保持),不符合上文的内容;B项containing意为"包括";C项obtaining意为"获取";D项sustaining意为"支撑,维持"。根据题意,选C。
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