在英语语法中，过去进行时是一个非常重要的时态，用于描述在过去某一特定时间或时间段内正在进行的动作。掌握这一时态的结构和用法，对于提高英语表达能力具有重要意义。
一、过去进行时的构成
过去进行时由 “was/were + 动词的现在分词（-ing形式）” 构成。具体规则如下：
- I/He/She/It 用 was
- You/We/They 用 were
例如：
- I was reading a book at 8 o’clock yesterday.
- They were playing football when it started to rain.
二、过去进行时的用法
1. 表示过去某一时刻正在发生的事情
常与 at that time, at 8 p.m. yesterday, when... 等时间状语连用。
- At 7 p.m. last night, she was cooking dinner.
- When I arrived, they were watching a movie.
2. 表示过去一段时间内持续进行的动作
常与 from 9 to 10, all day, during the week 等时间状语连用。
- He was working on his project all morning.
- We were traveling in Europe for two weeks.
3. 与一般过去时同时使用，表示两个动作同时发生
常用于 when, while 引导的时间状语从句中。
- While I was walking in the park, I saw a bird.
- She was studying when her friend called.
三、过去进行时的常见错误
1. 混淆一般过去时和过去进行时
一般过去时表示一个完成的动作，而过去进行时强调动作的持续性。
❌ I went to school yesterday.
✅ I was going to school when it started to rain.
2. 忘记使用“was/were”
直接使用动词原形是错误的。
❌ She running in the park.
✅ She was running in the park.
3. 主谓不一致
主语为单数时用 was，复数时用 were。
❌ They was talking.
✅ They were talking.
四、专项练习题
一、选择正确的答案：
1. At this time yesterday, I ______ (do) my homework.
A. did
B. was doing
C. do
D. am doing
2. They ______ (play) basketball when it began to snow.
A. played
B. were playing
C. play
D. are playing
3. What ______ you ______ (eat) at 7 p.m. last night?
A. were, eating
B. was, eating
C. did, eat
D. are, eating
4. My sister ______ (sleep) when I called her.
A. was sleeping
B. slept
C. is sleeping
D. sleeps
5. We ______ (travel) around the world from 2010 to 2015.
A. traveled
B. were traveling
C. travel
D. are traveling
二、根据句子意思填空：
1. This time yesterday, I ______ (write) an email.
2. She ______ (study) English when I arrived.
3. They ______ (not watch) TV at 9 p.m. last night.
4. While I ______ (cook), my brother was cleaning the room.
5. The children ______ (play) in the garden when the rain came.
五、参考答案
一、选择题答案：
1. B
2. B
3. A
4. A
5. B
二、填空题答案：
1. was writing
2. was studying
3. were not watching
4. was cooking
5. were playing
通过以上练习，希望你能更好地理解和掌握过去进行时的用法。多做练习、多听多说，才能真正掌握这一重要语法点。
