have been 和 had been的区别

问题描述:

have been 和 had been的区别
分别在什么情况下使用呢

一楼说的对,have been 用在现在完成时态中,如:I have been here for ten years.They have been to Shanghai for a long time.had been 用于过去完成时中.如:I had been to XI'an before I went to Beijing.在我去...