He realises that he has_____ about himself中,空格里为啥要用have been

He talks about Rome___he had been there himself 请从语法角度分析句子He is selfish,only caring about himself.里care为什么要用 He has been a teacher for ten years.=He has_____ ______ a te he will have been playing on the piano by that time 为什么要用on He must have been asleep at that time,(wasn't) he?为什么是用 wasn Has Jim come ____?Yes,he has_____ been here for ten minutes. 完成练习选择最佳答案1.Has Tom come_____?Yes.He has_____ been here for 英语选择 What ___was that he should have been awarded i'm surprised that he should have been so foolish he is so angry that he could _____say anything 空格里填（几乎不） He said that he (teach)himself how to He realized that he had revealed himself intentionally.