■基本用法
过去完成时由“had＋动词的过去分词”构成。主要表示在过去某一时刻或某一动作之前已经完成了的动作，即“过去的过去”。如：
The weather was worse than I had expected. 天气比我预料的要糟。
When I turned around, the boy had disappeared. 我一转身男孩就不见了。
He said he had come in through the window 他说他是从窗户进来的。
有时表示从过去某一时刻开始一直延续到另一过去时刻的动作或状态。跟现在完成时一样，也常与how long, for three days等表示一段时间的一类状语连用。如：
He asked how long I had lived there. 他问我在那儿住过多久。
■与一般过去时的比较
从用法上看，一般过去时表示过去某时发生的动作或存在的状态，而过去完成时则表示过去某一时间以前(即过去的过去)发生的动作或存在的状态。但是，当几个过去的动作用and, then, but等连接，且按照动作发生的先后顺序表达时，几个动作均可用一般过去。如：
He got up, washed his face, and went out. 他起床后就洗脸，然后就出门了。
请比较下面两句：
I bought a lighter, but lost it the next day.作比较。
I lost the lighter I had bought the day before. 我遗失了前天买的打火机。
另外，由after, before, as soon as 等连词引导时间状语从句，由于这些连词已经清楚地表明了主从句谓语动词的先后顺序，所以对于先发生的动作也可用一般过去时表示。如：
I told them the news after you (had) left. 你走后我把这消息告诉了他们。
■表示未曾实现的想法
表示想法或打算的动词，如hope, want, expect, think, suppose, plan, mean, intend等的过去完成时，后接不定式to do时，可以表示未曾实现的想法，即“本想做某事(但却没做)”。如：
I had meant to go on Monday but have stayed on. 我本想礼拜—走的，但又留下了。
We had thought to return early but they wouldn’t let us go. 我们本想早回来的，但他们不让我们走。
■使用过去完成时的句式
有的句式的谓语动词习惯上要用过去完成时。如：
Hardly had he arrived when she started complaining. 他刚到她就抱怨起来。(hardly…when…句式的主语通常要用过去完成时)
I had no sooner closed the door than somebody knocked. 我刚把门关上就有人敲门。(no sooner…than…句式的主语通常要用过去完成时)
It was the first time he had been bitten by a dog. 这是他第一次被狗咬。(it was the first time…句式的从句谓语通常要用过去完成时)