We___for her because she never came.A.shuldn't had waited B.shuldn't have waited

问题描述:

We___for her because she never came.A.shuldn't had waited B.shuldn't have waited
为什么?

选B
should have done表示本应该做而没有做
should not have done 表示本不该做而做了
再者should后面当然要接动词原形了,不会是had