过去完成时用于表示在过去某一时间点或事件之前已经完成的动作或状态。以下是一些过去完成时的例句：
By the time I went outside, the bus had already left.
我到外面去的时候，车已经开走了。
When I got to school, I realized I had left my backpack at home.
当我到达学校的时候，我意识到我把背包落在家里了。
Mr. Smith died yesterday. He had been a good friend of mine.
史密斯先生昨天去世了。他是我的好朋友。
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。
He said that he had known her well.
他说，他很了解她。
I thought I had sent the letter a week before.
我以为前一周我寄了那封信的。
After he arrived in England, Marx worked hard to improve his English.
马克思到英国后，他努力提高他的英语水平。
When I woke up, it had already stopped raining.
当我醒来时，雨已经停了。
We had hoped to be able to come and see you.
我们希望能被允许来看你。
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。
I had finished reading the novel by nine o'clock last night.
到昨晚9点钟，我已经读完这本小说。
They had already left.
他们已经离开了。
I had already eaten dinner.
我已经吃过晚饭了。
She had already去过那个地方了.
她已经去过那个地方了。
If I’d left sooner, I'd have been on time.
要是我早点动身，我就准时到了。
If we had found him earlier we could have saved his life.
要是我们当时早点找到他的话，我们就可以救活他。
If I had known that you were coming I would have met you at the air-port.
要是我早知道你要来的话，我就会在机场接你了。
If he had lived, some day Michael would have done something important.
假定麦克尔当时在世的话，他本可做出了不起的事。
If I had known how he felt, I would never have let him adopt those children.
我要是知道他的想法，我是决不会让他领养那些孩子的。
He would have forgotten the boy’s birthday if you hadn’t reminded him.
要不是你提醒他，他会忘记这男孩的生日的。
Our lives would have been greatly impoverished if we had not known our dear friend.
若不是得识我们这位好朋友，我们的生活一定十分不妙。
这些例句展示了过去完成时在描述过去事件中的时间顺序和逻辑关系方面的应用。希望这些例子对你有所帮助。