how to use them
had been是过去的过去，也就是在过去某个时间之前就已发生的事情
has/have been则是从现在时刻看已经完成的事情
一般说来，当用前者时句中还应有另一表过去的谓语动词或表过去的时间，如
I had been 17 years old when I left high school.
I had been 17 years old by this time of last year.had been 是has、havebean的过去形式啊，就是had是have/has的过去式。表示过去完成用had bean，表示现在完成用has/have bean
had been 表示过去完成的
has/have been 表示现在完成的
T o go to the bookshop to buy the book about the questions.