jumping with a dog. 6. I was cleaning my room When the fire broke
out,
Exercises
7. I was walking in the street when the accident happened.
8. When you have a meeting, you should turn off your mobile phone.
Unit3 What were you doing when the UFO arrived?
八道沟镇中学 赵媛霖
过去进行时的概念及构成
概念：表示过去某一时刻或某段时间正在进行 的动作 构成：主语+was/were+doing sth+时间状语
指示词：then、 at that time、once等连用，或 者用另一动作来表示过去的时间。
The weather was fine while we were in Beijing. She called while I was out. 如果主句的动作在从句的动作过程中发生，从句常用
进行时，如： While we were swimming someone stole our clothes Don’t talk so lould while others are working.
如：Mary was having dinner when I saw her. The boy was still sle
yesterday evening.
When与while引导的时间状语从句
While表示“在…时候”、“在…期间”。它强调主句 的动作与从句的动作同时发生，或主句的动作发生在 从句的动作过程中。While从句必须是表示动作或状态 的延续性动词。如：
Summary
1.When可指时间点，又可指时间段，从句 中可用延续性动词，也可用非延续性动 词。
2.While总是指一个时间段，从句中必须用 延续性动词。
3.统一时态：主句过去式，从句也是过去 式。
Exercises: fill with “while” or “when”
1. While May was talking on the phone,her sister walked in
when和while的用法与区别
1、延续性动词与非延续性动词
延续性动词指动作可以延续一段时间，而不是瞬间结束。
如：work study drink eat 等
非延续性动词指动作极为短暂，瞬间结束。
如：start begin hit jump knock等
When与while引导的时间状语从句
When表示”当…时候”。从句中既可以用延续性动词， 又可以用非延续性动词，这些动词既可以表示动作， 又可以表示状态。从句中的动作既可和主句动作同时 发生，又可在主句动作之前或之后发生。
up suddenly.
谢谢观赏
What are dreams? Dreams are one of those things that keep you going and happy.
梦想是什么？ 梦想是让你感到坚持就是 幸福的东西。
9. When you have PE class, you should wear sports shoes.
10. While I was doing my homework, the phone rang. 11. While it was raining, the plane took off. 12. While the teacher was speaking to class, he stood
2. When Rita bought her new dog,it was wearing a little coat.
3. When I saw Carlos , he was singing louldly. 4. While I was dancing , he was singing louldly. 5. When Linda finally saw David, he was