问题详情:
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
【回答】
D
知识点:过去完成时及其被动式
题型:选择题
问题详情:
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
【回答】
D
知识点:过去完成时及其被动式
题型:选择题