had been down是什么时态
had been done表示过去的过去，是过去完成的被动态时。
例句
I couldnt make out how it had been done.
我原来还不明白这是怎么回事。
They saw the job had been done.
他们看到工作已经做了。
So far all my book writing had been done in framemaker.
到目前为止，我所有的书籍写作都是在排版工具中完成的。
I was not able to tell him that the magic had been done to me.
我真不知道该怎么样告诉他，我所做的那套绝招是个什么样子？
Justice had been done even before the man was handed over to the police.
甚至在那人还没被送交给警察之前，正义就已得到了伸张。
