题目内容
【题目】Experiments of this kind___in both the U.S. and Europe well before the Second World War
A.have conducted
B.have been conducted
C.had conducted
D.had been conducted
【答案】D
【解析】句意:第二次世界大战之前,在美国和欧洲就曾彻底地进行过这种实验。本题考查时态与语态。experiments与conduct之间为被动关系,故排除A和C项。conduct这一动作发生在第二次世界大战之前,即过去的过去,所以用过去完成时,故选择D项。

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