过去完成时的四种用法

（1）过去完成时表示在过去某一时间或动作以前已经完成了的动作。（2）表示动作在过去某一时间之前开始，一直延续到过去的这一时间，而且还可能继续下去的动作，常和for, since构成的短语或引导的从句连用。（3）用于表示与过去事实相反的虚拟条件从句或as if从句中表示与过去事实相反。

（1）过去完成时表示在过去某一时间或动作以前已经完成了的动作。这个过去的时间状语有by, before等介词短语或when, before等引导的从句。

Helen had left her keys in the office so she had to wait until her husband came home. 海伦把钥匙忘到办公室里了，因此她不得不等她丈夫回来。

When we got to the cinema, the film had already begun.当我们到达电影院时，电影已经开始了。

He told me that he had visited the Great Wall before.他告诉我他以前参观过长城。

By the end of the match, they had kicked 2 goals, and we had kicked 4.比赛结束时，他们踢进了2个球而我们踢进了4个球。

When Jack arrived he learned Mary had been away for almost an hour.杰克到达后得知玛丽走了近一个小时了。

（2）表示动作在过去某一时间之前开始，一直延续到过去的这一时间，而且还可能继续下去的动作，常和for, since构成的短语或引导的从句连用。

The news came as no surprise to me. I had known for some time that the factory was going to shut down. 听到这个消息我并不感到吃惊。工厂要倒闭这件事我早就知道了。

By the time I left the school, he had taught the class for 3 years.到我毕业时，他已经教那个班三年了。

He said he had made great progress since he came here.他说自从他来这里他已经取得了很大进步。

（3）用于表示与过去事实相反的虚拟条件从句或as if从句中表示与过去事实相反

If he had seen you yesterday, he would have asked you about it.假如他昨天看到你，他就会问你这件事了。

I should have called you if I had known your telephone number.假如我过去知道你的电话号码，我就给你打电话了。

He described the scene as if he had been there.他描绘的景色如同他去过那里一样。

Had I known that you wanted the book, I would have sent it.如果我知道你要这本书，我会送来的。

（4）表示假设的宾语从句

放在像said，told，asked，thought，wondered等过去时动词的后面，表示在这些动作发生之前已经发生了的事情。

My friend told me that he had passed the exam.我的朋友告诉我，他已通过了考试。

He asked me whether I had seen the film the night before.他问我头一天晚上是否看过那部电影。