什么是should been?

什么是should been? Should Have Been 歌词 should have been有should had been吗 He should have been at boarding school should have been It should have been left Should Have Been You 歌词 The book you borrowed from the library should been returned in five days.那什么.为什么不是The book you borrowed from the library should be returned in five days.为什么是“been”不是“be”? should have done与should have been done的区别? I should already have been mature I/we should have been working.是什么意思 should have been doing表示什么情况? If human beings had been a bit less greedy and cruel,more birds and animals______dying out.a.ought to avoid b.could have been avoided c.should have avoided d.would have a dvoided为什么是D呢? I should have never been there应该怎么翻译 should have been booked a while ago翻译 We should have been so down well的中文翻译是什么 i'm surprised that he should have been so foolish This medicine should have been taken before dinner如何译 nobody should have been able to enter without permission翻译