英语 反义疑问句
书上说反义疑问句must的用法时提到如果表示推测则根据must之后的动词来确定：
1.It must have rained last night,didn't it?
2.He must have studied English for many years,hasn't he?
为什么都是现在完成时第一句话用的是didn't而第二句用的却是hasn't?难道是因为it的缘故?
反义疑问句中还有提到,如果之前的是I am,则之后要用aren't I.反过来说,之前用的是I am not,则之后要用are I 因为例题中没有所以有点怀疑求解.