分类：教育/科学-学习帮助
问题：whatisdifferentbewteenHadBeenand? 
how to use them 
回答：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.