过去完成进行时是由 had been+现在分词构成，因此无人称变化：
I had/I’d been working
they had not/hadn’t been working
had you been working?
had you not/hadn’t you been working?
凡不能用于进行时的动词均不能有这种时态，但动词want(有时还有wish)除外：
The boy was delighted with his new knife.He had been wanting one fora long time.
男孩对新小刀很高兴，他早就想要一把了。
注意：这一时态没有被动语态，像They had been picking ap-ples(他们一直在摘苹果)这样的句子，最近似的被动式是Ap-ples had been picked(苹果已摘完)，实际上这两种说法意思并不相同。(参见下面B3。)
B 用法
过去完成进行时与过去完成时之间的关系，同现在完成进行时与现在完成时之间的关系相同。
1 表示动作在所说的过去某一时刻之前就已开始并持续到那一时刻或者在那一时刻之前刚刚停止时，常常可以用两个时态中的任一个(参见第192节A)：
It was now six and he was tired because he had worked since dawn.
已经6点了，他感到很累，因为他从天亮起一直工作到现在。相当于：
It was now six and he was tired because he had been working since dawn.
那时正是6点，他因从一大早就干活而累了。
2 用过去完成时表示的反复的动作，有时可以作为一种连续的动作用过去完成进行时表示：
he had tried five times to get her on the phone.
他曾试着打了五次电话要找她。
He had been trying to get her on the phone.
他一直在试着打电话找她。
3 一个用过去完成时表达的单一动作和一个用过去完成进行时表达的动作不同(参见第192节C)：
By six o’clock he had repaired the engine.
到6点钟时他已经修好发动机了。(这项工作已经完成。)
但He had been repairing the engine(他一直在修理发动机)仅告诉我们他在前面的时间/前半小时里做什么，而并不告诉我们这项工作是否完成。
另一个区别是，由过去完成进行时表示的动作常持续进行直到或甚至超过说话的时间(这个时间是在过去)。而由过去完成时表示的动作虽可以发生在这一说话时间之前不久，但动作与说话之间可以有较长的时间间隔：
He had been painting the door.
他当时一直在油漆门。(油漆大概还未干。)
He had painted the door.
