was doing、had been doing和had been done都有什么区别?was doing和had been doing不是都是指过去一段时间做的事情吗?他们俩有什么区别吗?had been doing 和 had been done 又有什么区别.话说我在写英语句子时不知道什么时候该加ing...怎么办TAT

was doing 过去进行时
had been doing 过去完成进行时
had been done 过去完成时的被动式

was doing 过去进行时，虽然是过去某段时间的动作，但是它的时间参照物是现在
had been doing 过去完成进行时，是过去的过去，时间参照物是过去
had been done 过去完成时的被动语态，表示在过去的过去某个动作已经被完成了

was doing是过去进行时,表示过去正在发生.例如：She was washing when her son came in.（她儿子进来时她正在洗衣服.）
had been doing是过去完成进行时,基本相当于过去完成时,但可以强调动作延续.例如：They had been playing chess for the whole afternoon when their father went back from work.（他们的父亲下班回来时,他们已经下了一下午棋了.）
had been done是过去完成时的被动式,和前两个没有关系.例如：When the firemen got to the building,the fire had been put out.（等消防员感到那栋大楼的时候,火已经被扑灭了.）