过去完成时(The Past Perfect Tense)：
表示过去某一时间前就已经发生或完成了的动作，对过去的某一点造成的某种影响或是结果，用来指在另一个过去行动之前就已经完成了的事件。在英语时态中，“时”指动作发生的时间，“态”指动作的样子和状态。 它表示动作发生的时间是“过去的过去”，侧重事情的结果。
By nine o’clock last night, we had got 200 pictures from the spaceship.到昨晚9点钟，我们已经收到200 张飞船发来的图片。
I had been at the bus stop for 20 minutes when a bus finally came.当车来的时候，我在车站已等了20分钟。
He said he had worked in that factory since 1949.他说自从1949年以来他就在那家工厂工作。
Mr. Smith died yesterday. He had been a good friend of mine.史密斯先生昨天去世了。他以前是我的好友。
I didn’t know a thing about the verbs, for I had not studied my
lesson.我对动词一无所知，因为我没有好好学习功课。
I returned the book that I had borrowed.我已归还了我借的书。
She found the key that she had lost.她丢失的钥匙找到了。
He said that he had known her well.他说他很熟悉她。
I thought I had sent the letter a week before. 我认为我一星期前就把信寄出去了。
When I woke up, it had already stopped raining.我醒来时雨已停了。
She didn’t go to bed until she had finished he work.她直到把工作做完之后才睡觉。
After he arrived in England, Marx worked hard to improve his English.
马克思到达英格兰之后，努力提高他的英语水平。
They had wanted to help but could not get there in time.他们本来打算去帮忙，但没有及时赶到那里。
We had hoped to be able to come and see you .我们本来希望能来看看你。
Hardly had he began to speak when the audience interrupted him.他刚开始演讲，听众就打断了他。
No sooner had he arrived than he went away again.他刚到就又走了。
It was the third time that he had been out of work that year.这是他那一年第三次失业了