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

admin2014-09-24  35

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.
【C1】

选项 A、times
B、schedules
C、plans
D、timing

答案A

解析 times作为"时代"讲,可用复数形式。如ancient times(古代)。timing是名词,意思是"对时间的确定和选择"。schedule的意思是"计划,日程安排"。它与timeta—ble相近,另也有plan和arrangement的意思。本题应选A。
转载请注明原文地址:https://jikaoti.com/ti/ewIYFFFM
0

最新回复(0)