过去完成时用于描述在过去某个时间或动作之前已经发生或完成的动作，即“过去的过去”。以下是一些过去完成时的例句：
在我睡觉之前，我已经读了一些书。
Before I went to bed last night, I had read some books.
当我到达学校时，我意识到我把背包落在家里了。
When I got to school, I realized I had left my backpack at home.
我们已经到了电影院，但是电影已经开始了。
We had already arrived at the cinema, but the movie had already started.
我已经吃过晚饭了。
I had already eaten dinner.
在警察到达之前，小偷已经逃跑了。
The thief had run away before the police arrived.
史密斯先生昨天去世了。他是我的好朋友。
Mr. Smith died yesterday. He had been a good friend of mine.
我对动词一无所知，因为我没有好好学习功课。
I didn’t know a thing about the verbs, for I had not studied my lesson.
他说，他很了解她。
He said that he had known her well.
我以为前一周我寄了那封信的。
I thought I had sent the letter a week before.
到昨晚9点钟，我已经读完这本小说。
I had finished reading the novel by nine o'clock last night.
我们刚离开家就开始下雨了。
No sooner had we left the house than it began to rain.
我没有走多远就赶上他们了。
I had not gone much farther before I caught them up.
昨晚九点前我们已完成了工作。
We had finished the work by nine o'clock yesterday.
到1999年底公司已完成了那个项目。
The company had completed the project by the end of 1999.
这个东西，我找了好多天才找着。
I had been looking for it for days before I found it.
电话铃响了三分钟才有人接。
The telephone had been ringing for three minutes before it was answered.
他工作了一整天，所以他累了。
He was tired. He'd been working all day.
布朗教授讲了半小时课之后，他喝了一点水。
After he'd been lecturing for half an hour, Professor Brown had a drink of water.
这些例句展示了过去完成时在不同的语境和结构中的用法，希望对你有所帮助。
