1)have +过去分词，构成完成时态，例如：

　　He has left for London.　他已去了伦敦。

　　By the end of last month, they had finished half of their work.

　　上月未为止，他们已经完成工作的一半。

　　2)have + been +现在分词，构成完成进行时，例如：

　　I have been studying English for ten years.

　　我一直在学英语，已达十年之久。

　　3)have+been +过去分词，构成完成式被动语态，例如：

　　English has been taught in China for many years.

　　中国教英语已经多年。