过去完成时是英语中的一种时态，用于表示过去某个时间点之前发生的动作或事件，通常是由“had + 过去分词”构成。下面是五个过去完成时的句子：
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我已经吃过早饭了，当我到达学校时已经是九点钟了。
I had already had breakfast when I arrived at school at nine o'clock.
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她很失望，因为她已经买了票，但演出却被取消了。
She was very disappointed because she had bought the tickets, but the show was cancelled.
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我们在去机场的路上堵车了，所以我已经打电话给他们告诉他们我们会晚到。
We got stuck in traffic on the way to the airport, so I had already called them to let them know we would be late.
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警察问他在这个时间点是否在家，他回答说他已经去了超市。
The police asked him if he was at home at that time, and he answered that he had already gone to the supermarket.
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她打开信封，发现她已经收到了录取通知书。
She opened the envelope and found that she had already received the acceptance letter.
以上是五个常见的过去完成时的句子，掌握这个时态的用法可以让你的英语更加流利自然。
