should have been doing表示什么情况?
英语中的“过去将来完成进行时”通常用于什么情况?would/should have been doing结构
must have been doing与must have been done都表示推测,有什么区别呀?
have,has,have been,has been在什么情况下用啊?
英语时态区分have done .have been doing.had done.had been doing.有什么
to have been doing 和 having been doing 有什么区别,重点是have 和having
have been doing sth
have been doing 和have+过去分词有什么不同?
Should Have Been 歌词
have been done 和 have been doing
would have been completed表示什么时态?
have been on 跟 have been doing有什么区别吗?
will have been doing和have been doing的区别