had been doing這是過去完成進行時;表示從過去的某一個時間點開始做某事一直持續到過去的某個時間點并且仍在進行。放在間接引語或虛擬語氣中時它的時態不能再向前推，向后推是現在完成進行時。

雙語例句

1、Benjamin was forced to admit what he had been doing.

本杰明被迫承認他所做的一切。

2、I had told people what he had been doing, so now the police were onto him.

我已將他的所作所為告訴了別人，因此現在警方正在追查他。

3、Until this summer, China had been doing that carefully.

截止今年夏天，中國一直在審慎地這么做。

4、I had been doing the work for two hours when the teacher came.

老師來時那件工作我已做了兩小時了。&當時工作尚未完成，所以老師來了我還繼續在做。

5、Everybody knew what he had been doing all those years.

had been doing 和had been done的差別

1、首先要區分has been done與 had been done的區別：

have/has been done 是現在完成時的被動語態。表示某事被做，。

如：The problems have been solved.這些問題已經被解決了。

had been done 則是過去的過去，是過去完成的被動態時。(當你想說發生在過去的兩件事時，就要分清誰先誰后。先發生的用過去完成時，后發生的要用過去時)。

如：The rooms had been cleaned when I came. 我來的時候，房間已經被打掃了。

2、區分has/have been doing與 had been doing

has/have been doing是現在完成進行時，并對現在有影響。

如句子：I have been dreaming all the night.

had been doing是過去完成進行時，也是過去的過去，需要時間先后順序的對比.

如：I had been doing the cleaning before my mother arrived at home.