be supposed to 和should have done

题目

be supposed to 和should have done
WAS SUPPOSED TO表示应该做某事而未做
WAS NOT SUPPOSED TO表示不应做某事却做了
SHOULD HAVE DONE 表示因该做某事而未做
SHOULD NOT HAVE DONE表示不应做某事却做了
WAS SUPPOSED TO表示应该做某事而未做
这四个有什么关系的?比如两两相等用法?

答案

be supposed to=shouldbe not supposed to= shouldn't完全相等 就表示应该做什么 前者有不同时态 后者没有时态区分was supposed to 过去应该做某事 事实就是没做 强调过去的那个时候应该发生 时间should have done ...