《时间状语从句》PPT课件
一、什么是时间状语从句？
在英语中，时间状语从句是用来表示主句动作发生时间的从句。它通常由一些特定的连词引导，如：when, while, as, before, after, until, since, as soon as, by the time 等。
这些从句可以帮助我们更清楚地表达事件发生的先后顺序或同时性。
二、常见的时间状语从句引导词及用法
1. when
- 表示“当……的时候”，主句和从句的动作可以是同时发生，也可以是先后发生。
- 例句：
- I was watching TV when he called.
- She arrived when the meeting had already started.
2. while
- 强调两个动作同时发生，常用于进行时态。
- 例句：
- He was cooking while his sister was doing homework.
- While I was walking in the park, it started to rain.
3. as
- 也表示“当……的时候”，强调动作的同时性，有时带有“随着”的意思。
- 例句：
- As the sun rose, the birds began to sing.
- She smiled as she read the letter.
4. before
- 表示“在……之前”，强调主句动作发生在从句动作之前。
- 例句：
- We left before it started to snow.
- He finished his work before the deadline.
5. after
- 表示“在……之后”，强调主句动作发生在从句动作之后。
- 例句：
- I called her after I got home.
- They started the meeting after the guest arrived.
6. until
- 表示“直到……为止”，常与否定词连用，表示“直到……才……”。
- 例句：
- I didn’t leave until the teacher dismissed us.
- She stayed until the end of the party.
7. since
- 表示“自从……以来”，常用于现在完成时。
- 例句：
- I have lived here since 2015.
- She has been working since morning.
8. as soon as
- 表示“一……就……”，强调动作的立即性。
- 例句：
- I will call you as soon as I arrive.
- She started crying as soon as she saw the result.
9. by the time
- 表示“到……时候为止”，强调截止时间点前已经完成的动作。
- 例句：
- By the time we arrived, the movie had already started.
- He had finished his homework by the time his mother came back.
三、时间状语从句的时态搭配
在使用时间状语从句时，要注意主句和从句的时态搭配，常见的有以下几种情况：
1. 主句用一般过去时，从句用一般过去时
- 例句：
- I met him when I was in Beijing.
2. 主句用一般将来时，从句用一般现在时
- 例句：
- I will call you when I get there.
3. 主句用现在完成时，从句用一般现在时
- 例句：
- She has already left since she got up early.
4. 主句用过去完成时，从句用一般过去时
- 例句：
- I had finished my homework before he arrived.
四、练习与巩固
练习1：选择合适的连词填空
1. I will call you ______ I arrive at the station.
2. She was reading a book ______ the phone rang.
3. He didn't go out ______ it stopped raining.
4. We waited for an hour ______ the bus finally came.
5. I didn't know the truth ______ I heard it from her.
答案：
1. as soon as
2. when
3. until
4. until
5. until
五、小结
- 时间状语从句是英语中非常重要的语法结构，能帮助我们准确表达动作发生的时间关系。
- 常见的引导词有：when, while, as, before, after, until, since, as soon as, by the time。
- 注意主句与从句之间的时态搭配，确保逻辑清晰、语义明确。
希望这份PPT内容能够帮助大家更好地理解和掌握时间状语从句的相关知识！
---
如需进一步扩展为PPT格式（如分页、图表、例句展示等），也可以告诉我，我可以继续为你完善。
