there has been a time和there had been a time有什么区别?

问题描述:

there has been a time和there had been a time有什么区别?

区别就是
一个是现在完成时(there has/have been)
一个是过去完成时(there had been)、

都是there be句型的完成时态.区别就是一个是现在完成时(there has/have been),一个是过去完成时(there had been)、