They must have been to the USA,have not they?与He must have been to the USA,was not he?区别
问题描述：
They must have been to the USA,have not they?与He must have been to the USA,was not he?区别
最好讲讲为什么句子主语一换,must反义疑问句就不一样了?
答
你好,你没有搞懂这些句子的用法:在这两个句子中,因为都没有时间状语的修饰,所以句子发生的时间不确定,答案也不确定,请你看以下的句子,They must have been to the USA,haven't they?He must have been to the USA,ha...