Question

Experiments of this kind _______in both the U.S. and Europe well before the Second World War started.

A．have conducted	B．have been conducted
C．had conducted	D．had been conducted

Answer 1

D

试题分析：句意：在第二次世界大战之前这种实验就在美国和欧洲做过。因为时间状语before the Second World War started.这里的谓语动词是过去式，conduct是在这个动作之前的发生的动作，故用过去完成时，又因为experiments与conduct之间是被动关系，故选D。
点评：本题难度适中。动词的时态及语态放在一起考查增加了试题的难度，需要考生有分析理解复杂的句子结构的能力。
即学即练：In the last few years thousands of films_______ all over the world.
A.have produced   B. have been produced   C. are producing      D. are being produced
解析：B。句意：“在过去的几年时间里，全世界制作了成千上万部电影。”in the last few years在过去的几年时间里，其实是从过去算到现在，是现在完成时的标志。选B。