1)have +過去分詞,構成完成時態,例如:
he has left for london. 他已去了倫敦。
by the end of last month, they had finished half of their work.
上月未為止,他們已經完成工作的一半。
2)have + been +現在分詞,構成完成進行時,例如:
i have been studying english for ten years.
我一直在學英語,已達十年之久。
3)have+been +過去分詞,構成完成式被動語態,例如:
english has been taught in china for many years.
中國教英語已經多年。