过去进行时的被动语态结构是 was /were being +及物动词的过去分词，方法还是主动语句中的宾语变被动语态的主语，动词由主动变被动
1.表示过去某一时间以前已经完成的动作，常与by, before等引导的时间状语连用。
例句1：How many buildings had been destroyed when the hurricane ended?
例句2：Had the new plan been discussed before the meeting?
2.在 told, said, knew, heard, thought等动词之后的宾语从句中，若表示过去某一被动动作时，用过去完成时。
例句1：The boy was reminded that his homework had not been handed in.
例句2：The media reported more than 1,000 people had been killed in the earthquake.
3.根据语意可以判断出动作先后的被动语态，用过去完成时。
例句1：As the assignment had been done, he went on to search the Internet.
例句2：He did what he had been told to
另：当从句由 after，before，when或 as soon as引导时，主句和从句都可以用一般过去时。
例句1：When he arrived, he called her.
例句2：They locked the door before they left.
