Experimentofthiskind

问题详情：

Experiment 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

【回答】

D　考查动词时态和语态。主语experiment与conduct构成动宾关系，谓语使用被动形式。before the Second World War是过去的过去，故用过去完成时。

知识点：过去完成时及其被动式

题型：选择题