情态动词加上完成时的意思?
问题描述：
情态动词加上完成时的意思?
could not have done
must not have done
should not have done
would not have done
以及它们的用法?
答
could+have+done（过去分词）表示本来可能做的事却没有做.eg:You could have phone me.你本可以给我打电话.must+have+done表示对过去发生事情的猜测.eg：You must have heard the news.你一定已经听说了.should+have...