I don't think they must have finished file project by the end of last month ,______?为什么是had they?

分类: 作业答案 • 2021-12-19 15:23:24

问题描述：

I don't think they must have finished file project by the end of last month ,______?
为什么是had they?

答

by the end of last month 与过去完成时连用,所以是had they?must表推测的反意疑问句的有关用法 1）对现在情况的推测,问句部分用主动词（do,be)一般现在时的适当形式.若是现在进行时,问句部分用现在进行时的适当形式...