The scientist __________ the experiment for half a year, but he _______ yet.A.made; didn’t succeedB.

题目简介

The scientist __________ the experiment for half a year, but he _______ yet.A.made; didn’t succeedB.

题目详情

The scientist __________ the experiment for half a year, but he _______ yet.
A.made; didn’t succeedB.made; hasn’t succeeded
C.was making; didn’t succeedD.has been making; hasn’t succeeded
题型:单选题难度:中档来源:不详

答案

D
考查时态。根据for half a year可知应该使用完成时,再根据句意可知完成进行时符合句子的意思。Yet也和完成时连用。结合句意可知D正确。句意:半年来那位科学家一直在做那个实验,但他还没有成功。

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