什么是过去进行时？
过去进行时是英语中用来描述在过去某一特定时刻正在进行的动作或状态的时态。它强调过去某个时刻正在发生的动作，通常与另一个过去的动作或时间点有关。以下是一些例子，展示了过去进行时的用法：
- 过去某时刻正在进行的动作：
- At 5 PM yesterday, they were having dinner.（昨天下午5点，他们正在吃晚餐。）
- I saw them while they were playing soccer in the park.（我看见他们正在公园里踢足球。）
- 另一个过去动作的背景：
- She was reading a book when the phone rang.（电话响起时，她正在读书。）
- He was studying all night before the exam.（考试前一晚，他一直在学习。）
- 交替进行的动作：
- While I was working, he was watching TV.（当我在工作时，他在看电视。）
- They were dancing while the band was playing music.（乐队在演奏音乐的时候，他们在跳舞。）
- 过去的计划和安排：
- Last week, I was meeting with a client in New York.（上周，我在纽约和客户会面。）
- They were traveling around Europe during the summer.（夏季期间，他们在欧洲旅行。）
- 描写过去的环境或背景：
- The sun was setting, and the sky was turning orange.（太阳正在落山，天空变成了橙色。）
- It was raining heavily, and everyone was carrying umbrellas.（雨下得很大，每个人都拿着伞。）
过去进行时强调过去某个时刻正在发生的动作，常常用来描述另一个过去动作的背景或两个交替进行的动作。
1. 过去进行时的形式:
was/were + 现在分词
2. 过去进行时的用法:
1) 表示过去某一时刻正在进行的动作
* We were expecting you yesterday. 我们昨天一直在等你。
* What book were you reading when I saw you at four yesterday afternoon? 昨天下午四点我看见你时，你在看什么书？
* I wasn’t having a talk with Li Hua at that time. 那时我没在跟李华谈话。
* Was he watching TV when you came back? 你回来的时候，他正在看电视吗？
* Kate was reviewing her lessons at eight last night. 昨晚8点的时候凯特正在复习功课。
* While my mother was watching TV, I was making a kite. 我妈妈在看电视的时候，我在制作风筝。
2) 描绘一幅景象或故事背景
* Last Sunday, I went and sat on the river bank as usual. Some children were playing games on the bank and there were some people rowing on the river. 上星期天，我和往常一样，又去河边坐着。河岸上有些孩子正在玩耍，河面上有些人正在划船。
* It was snowing as the medical team made its way to the front. 那支医疗小组往前线行进时，天正下着雪。
3) 表示按计划、安排过去某时将要发生的动作
* A train was leaving at midnight for Beijing. 半夜有一趟列车开往北京。
* They said that they were going back to their own country. 他们说他们将回自已的国家。
4) 与always, constantly, continually, forever 等连用，表示感情色彩
* She was constantly complaining of the cold. 她总抱怨天气太冷。
* He was always making noises. 他总爱大声喧闹。
* He was always thinking of his work. 他总是一心想着他的工作。
* She was forever complaining. 她老是抱怨。
