Question

【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

Answer 1

【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。