在过去完成时态的学习中，我们主要探讨的是在过去的某个时间点之前已经完成的动作或状态。这种时态通常用于描述两个过去的动作之间的关系，其中一个是先发生的，另一个是后发生的。为了帮助大家更好地理解和掌握这一语法点，以下是一些精心挑选的练习题，供学习者参考。
一、单项选择题
1. By the time she arrived at the station, the train _______ already left.
A) has B) had C) was D) would
2. When I got home, my brother _______ his homework.
A) finished B) had finished C) finishes D) was finishing
3. They _______ the movie when we came into the cinema.
A) have seen B) saw C) had seen D) were seeing
4. By 2020, he _______ in the company for ten years.
A) worked B) had worked C) has worked D) will work
5. She realized that she _______ her keys at home.
A) lost B) had lost C) loses D) was losing
二、改写句子
将下列句子改为过去完成时态：
1. He opened the door and found the room empty.
→ He _______ the door and _______ the room empty.
2. She called me after she finished her work.
→ She _______ me after she _______ her work.
3. The teacher explained the problem after the students asked questions.
→ The teacher _______ the problem after the students _______ questions.
三、情景对话
假设你在一家咖啡馆遇到一位老朋友，你们聊起了各自的经历。请根据以下提示编写一段对话，并使用过去完成时态。
提示：
- 你提到自己去年夏天去了巴黎。
- 你的朋友说他之前也去过巴黎，但是在十年前。
- 你还提到在去巴黎之前，你已经学了一年的法语。
通过以上练习，希望大家能够更加熟练地运用过去完成时态来表达复杂的时态关系。语法的学习需要不断实践和巩固，希望大家在日常生活中多加注意，逐渐形成自然的语言习惯。如果你对某些题目有疑问，欢迎随时提问！
