初一下册英语第四单元讲义unit 4 语法篇

Unit 4 语法篇

祈使句

一、祈使句指的是表示命令、请求、建议或劝告的句子。其主语you常省略，谓语动词用原形，句末用感叹号或句号，读降调。

二、祈使句的肯定句式一般分为以下三种类型：

1.行为动词原形＋其它成分。例如：

Make sentences after the model.根据例句造句。

2. Be动词＋其它成分(形容词、名词或介词短语等)。例如：

Be careful when crossing the street.过马路时要小心。

3. Let＋宾语＋动词原形＋其它成分。例如：

Let him go back now.让他现在回去吧。

三.祈使句的否定句式

祈使句的否定句式，通常情况下在句首加上Don’t或Never，一般分为以下四种类型：

1.在祈使句的肯定句式前加Do’t，构成『Don’t＋行为动词原形＋其它成分』。例如：

Don’t say that again!别再那样说了！

2.在Be动词引起的肯定祈使句前加Don’t，构成『Don’t be＋其它成分(形容词、名词或介词短语等)』。例如：Don’t be careless.不要粗心。

注意：在这种句型中be不能省略；否定副词not不可置于be之后。

3. Let引起的祈使句的否定形式有两种：

(1)Let开头的祈使句，如果后面跟第一、第三人称名词或代词的宾格，可在Let前加Don’t，也可在Let后宾格的名词或代词后面加not。

(2)如果以Let’s开头的祈使句，必须在Let’s后加not。例如：

Don’t let me go with her tomorrow. ＝Let me not go with her tomorrow.

不要让我明天跟她一起去。

Let’s not tell her the truth whenever we meet her.

无论什么时候我们碰到她，都不要告诉她真相。

4.在公共场合的提示语中，否定祈使句常用『No＋名词/V-ing形式』结构，表示『禁止做某事』。例如：

NO PHOTOS! 禁止拍照！

四.祈使句的反意问句

祈使句的反意疑问句须按其句子结构及讲话人的语气来决定其疑问部分。通常有以下三种形式：

1.祈使句为肯定句式，其反意疑问句表示请求时，通常用will you；表示邀请、劝说时，用won」t you。例如：

Be sure to write to us, will you? 你一定要给我们写信，好吗？

Come to have dinner with us this evening, won’t you?

今晚来和我们一起吃饭，好吗？

2.祈使句为否定句式，其反意疑问句通常只用will you。例如：

Don’t smoke in the meeting room, will you?

不要在会议室抽烟，好吗？

3. Let开头的祈使句构成反意疑问句时，除Let’s用shall we外，其它均用will you。例如：

Let the boy go first, will you? 让个那男孩先走，好吗？

Let’s take a walk after supper, shall we?

晚饭后我们去散步，好吗？

情态动词

1. Look! The traff ic light has turned red. We _____ stop our car.

A. can

B. can’t

C. must

D. mustn’t

2. Nowadays .all passengers go through safety check before take a train.

A. can

B. may

C. must

D. will

3. —Mr. Wang, must I come again to clean the classroom on Sunday?

—No, you____ . I have asked Kate to do it.

A. can’t

B. mustn’t

C. needn’t

D. shouldn’t

4. Daniel, ___ play with the mobile phone while you're walking in the street.

A. don't

B. doesn't

C. won't

D. can't

5. kind and helpful to the people around us, and we will make the world a nicer place to live in.

A. Be

B. Being

C. To be

D. Been

6. ________ in bed. It’s bad for your eyes.

A. Not to read

B. Don’t read

C. Don’t to read

D. Not read

一、单项选择

1. picture books in class, please.

A. Not read

B. No read

C. Not reading

D. Don't read

2. Ssh! talk loudly. The baby is sleeping right now.

A. Do

B. Does

C. Don't

D. Doesn't

3. Do you wear a uniform at school?

A. must

B. have to

C. may

D. can

4. You stop when the traffic light turns red.

A. can

B. had better

C. need

D. must

5. --- you give your seat to this old man?

--- Of course.

A. Can

B. Shall

C. Need

D. Must

二、按要求转换句型

6. Throw that piece of paper away. (改为否定祈使句)

that piece of paper away.

7. Pick some flowers, please. (改为否定祈使句)

pick flowers, please.

8. I have to look after myself. (改为否定句)

I look after myself.

9. Andy has to study for a test. (改为一般疑问句)

Andy study for a test?

10. I can talk to Jenny's mother. (改为一般疑问句)

talk to Jenny's mother?

三、翻译(根据中文提示完成句子)

11. 请找布朗先生接电话好吗?

speak to Mr.Brown?

12. 在周末我喜欢去那儿，但是我得先做一些家务活。