在英语学习中，掌握时态是非常重要的。今天我们将重点探讨过去完成时，并通过一些练习题来巩固这一知识点。

什么是过去完成时？

过去完成时用来描述在过去某个时间点之前已经完成的动作或状态。它的结构是“had + 过去分词”。例如：

- I had finished my homework before dinner.

在这个句子中，“had finished”表明动作“finish”是在“before dinner”之前完成的。

练习题

1. She ______ (read) the book before she went to bed.

2. They ______ (not finish) their project by the time we arrived.

3. By the end of last year, he ______ (work) here for five years.

4. When I got home, my sister ______ (already leave).

5. Had you ______ (study) for the test when I called?

答案

1. had read

2. hadn't finished

3. had worked

4. had already left

5. studied

通过这些练习题，希望大家能更好地理解和运用过去完成时。记住，关键在于理解动作发生的先后顺序，并正确使用“had + 过去分词”的结构。

继续多做练习，你的英语水平一定会有所提高！