They must have done their homework yesterday,___?

来源：学生作业帮编辑：作业帮分类：英语作业时间：2024/05/26 02:32:05

They must have done their homework yesterday,___?
为什么是didn't they?
我觉得应该是haven't they啊?

must have done ：对过去事实的推测,不是现在完成（后者不能与明确的过去时间连用）.反义问句是问“昨天他们是否做了家庭作业”,当然用didn't they.
比较：
They have done their homework,haven't they?
They did their homework yesteday,didn't they?

They must have done their homework yesterday,___? They must have done their homework yesterday,____? They must have finished their homework,_______. WHAT MUST THEY DO?TH EY MUST DO THEIR HOMEWORK ( )They have finished their homework,and_______. They have been doing their homework They did not their homework yesterday.有什么语法错误? they ( )(not do)their homework yesterday适当形式填空 They must do their homework after school改为同义句 They must finsh their homework on Friday.改为同义句 the boys were playing.they must ---- their homework. must have been done must have done