Experiments of this kind in both the U.S. and Europe well before the Second Worl

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

试题答案

D

考查动词时态和语态，句意为“就在二战爆发前，美国和欧洲都进行过这种实验。”首先考虑语态，主语experiment与conduct构成动宾关系，谓语使用被动形式。题干中出现the second war是过去的时间点，before the second war是过去的过去，因此使用过去完成时。选D。