Unit 3 Diverse Cultures Discovering Useful Structures 课件 (共16张PPT)人教版（2019）必修第三册

(共16张PPT)
状语从句的省略
知识点1：什么是状语从句的省略？
- 定义：在特定条件下，状语从句中与主句重复的主语和谓语（多为be动词）可省略，使句子更简洁
- 原句：When he was walking in the park, he met a friend.
- 省略后：When walking in the park, he met a friend.
省略的核心条件（1）
- 条件1：主句和从句的主语必须一致
- 正确：While she was reading, she took notes. → While reading, she took notes.
- 错误：While she was reading, her brother came in.（主语不一致，不可省略）
省略的核心条件（2）
- 条件2：从句的谓语中必须包含be动词（am/is/are/was/were）
- 正确：If it is necessary, we will help you. → If necessary, we will help you.
- 错误：Because he worked hard, he succeeded.（谓语无be动词，不可省略）
常见可省略的状语从句类型（1）—— 时间状语从句
- 引导词：when, while, as（当……时）
- 省略形式：引导词 + 现在分词/过去分词/形容词/介词短语
- 例句：
- When (I was) waiting for the bus, I saw a car accident.
- While (he was) in London, he learned English.
常见可省略的状语从句类型（2）—— 条件状语从句
- 引导词：if, unless
- 省略形式：引导词 + 现在分词/过去分词/形容词/名词
- 例句：
- If (it is) possible, I will visit you tomorrow.
- Unless (you are) invited, don’t go to the party.
常见可省略的状语从句类型（3）—— 让步状语从句
- 引导词：though, although, even if, even though
- 省略形式：引导词 + 现在分词/过去分词/形容词
- 例句：
- Though (he was) tired, he kept working.
- Even if (I am) busy, I will attend the meeting.
常见可省略的状语从句类型（4）—— 方式/比较状语从句
- 引导词：as（按照）, than（比）
- 省略形式：保留核心词，省略重复部分
- 例句：
- Do as (you are) told.（方式状语从句）
- She is taller than (she was) before.（比较状语从句）
省略的具体形式（分情况）
1. 从句谓语为“be + 现在分词” → 省略“主语 + be”，保留“引导词 + 现在分词”
- 例：While (they were) discussing the plan, they had an argument.
2. 从句谓语为“be + 过去分词” → 省略“主语 + be”，保留“引导词 + 过去分词”
- 例：If (the bridge is) built, it will save time.
3. 从句谓语为“be + 形容词/介词短语” → 省略“主语 + be”，保留“引导词 + 形容词/介词短语”
- 例：When (he is) ill, he stays at home.
注意事项（1）—— 主语不一致时不可省略
- 错误示例：
- When crossing the street, a bike hit him.（省略后逻辑主语为“a bike”，与“crossing”的实际主语“he”不一致）
- 正确表达：
- When he was crossing the street, a bike hit him.
注意事项（2）—— 某些固定搭配的省略
- 常见固定省略结构：
- if necessary（如果有必要）
- if possible（如果可能）
- when necessary（必要时）
- though tired（尽管累）
1. While ______ (walk) in the forest, we saw a deer.
2. If ______ (accept) for the job, she will move to Beijing.
3. Though ______ (be) young, he knows a lot.
4. He didn’t speak until ______ (speak) to.
5. When ______ (be) in trouble, she always asks for help.
6. Unless ______ (invite), I won’t go to the party.
7. ______ (be) busy, she still found time to read.
8. Do as ______ (tell) and you’ll succeed.
9. While ______ (study) abroad, he made many friends.
10. If ______ (possible), I want to travel around the world.
11. Though ______ (defeat) many times, he never gave up.
12. When ______ (arrive) at the station, please call me.
13. She looks younger than ______ (be) ten years ago.
14. Even if ______ (rain), we will go hiking.
1. walking（While he was walking...）
2. accepted（If she is accepted...）
3. being（Though he is being young...）
4. spoken（until he was spoken to）
5. being（When she is being in trouble...）
6. invited（Unless I am invited...）
7. Being（Though she is being busy...）
8. told（Do as you are told...）
9. studying（While he was studying...）
10. possible（If it is possible...）
11. defeated（Though he was defeated...）
12. arriving（When you are arriving...）
13. being（than she was being ten years ago）
14. raining（Even if it is raining...）
- 总结：
1. 省略条件：主语一致 + 从句含be动词
2. 常见类型：时间、条件、让步等从句
3. 易错点：主语不一致时不可省略，避免歧义
- 作业：将下列句子改为省略形式（各2句）
- 时间状语从句：When I am free, I like reading.
- 条件状语从句：If it is fine tomorrow, we will have a picnic.