首页 > 第137-140课条件状语从句与情态动词

第137-140课条件状语从句与情态动词

Lesson 137-140 | 核心句型：你想买什么？、是不是、你能……吗？ | 语法点：if引导的真实条件状语从句、if引导的宾语从句、情态动词must/can/may的用法总结、反意疑问句

核心句型

1. 第137-138课你想买什么？

Shop assistant: Can I help you? 售货员：您买什么？

Customer: I want a pair of shoes, please. 顾客：我想买一双鞋。

Shop assistant: What size? 售货员：多大号的？

Customer: Size eight. 顾客：8号的。

Shop assistant: What colour do you like? 售货员：您喜欢什么颜色的？

Customer: Black, please. 顾客：请给我黑色的。

Shop assistant: I'm sorry. We haven't got any black shoes at the moment. But we have some brown ones. 售货员：对不起，现在我们没有黑色的鞋了。不过我们有一些棕色的。

Customer: Do you have any other colour? 顾客：你们还有其他颜色的吗？

Shop assistant: We have some white ones, too. Do you like them? 售货员：我们还有一些白色的。您喜欢吗？

Customer: No, I don't. I want black ones. 顾客：不，我不喜欢。我想要黑色的。

Customer: If I can't get black shoes, I will buy brown ones. 顾客：如果我买不到黑色的鞋，我就买棕色的。

Shop assistant: If you wait a minute, I will check if we have any black shoes in the back. 售货员：如果您等一会儿，我去后面看看我们是否还有黑色的鞋。

Shop assistant: Oh, yes! I found a pair of black shoes in size eight. 售货员：哦，有了！我找到了一双8号的黑色鞋。

Customer: Great! If they fit me, I will take them. 顾客：太好了！如果合适的话，我就买了。

2. 第139-140课是不是、你能……吗？

Graham: Is that you, John? 格雷厄姆：是你吗，约翰？

John: Yes, speaking. 约翰：是我，请讲。

Graham: Tell Mary we'll be late for dinner this evening. 格雷厄姆：告诉玛丽，今晚吃饭我们将晚到一会儿。

John: I'm afraid I don't understand. 约翰：恐怕我不明白你的意思。

Graham: Hasn't Mary told you? She invited Charlotte and me to dinner this evening. I said I would be at your house at six o'clock, but the boss wants me to do some extra work. I'll have to stay at the office. I don't know when I'll finish. Oh, and by the way, my wife wants to know if Mary needs any help. 格雷厄姆：玛丽没有告诉你吗？她邀请我和夏洛特今晚去吃饭。我说过我6点到你家，但老板要我加班。我得留在办公室。我不知道什么时候才能结束。哦，顺便问一下，我妻子想知道玛丽是否需要帮忙。

John: I don't know what you're talking about. 约翰：我不知道你在说什么。

Graham: That is John Smith, isn't it? 格雷厄姆：你是约翰·史密斯，对吗？

John: Yes, it is. 约翰：是的，我是。

Graham: You are John Smith, the engineer, aren't you? 格雷厄姆：你是工程师约翰·史密斯，对吗？

John: That's right. 约翰：对。

Graham: You work for the Overseas Engineering Company, don't you? 格雷厄姆：你在海外工程公司上班，是吗？

John: No, I don't. I'm John Smith the telephone engineer and I'm repairing your telephone line. 约翰：不，我不在。我是电话工程师约翰·史密斯，我正在修理你的电话线。

Graham: Oh, I'm very sorry. I think I must have dialed the wrong number. 格雷厄姆：哦，非常抱歉。我想我肯定拨错号码了。

John: It doesn't matter. 约翰：没关系。

语法知识点

1. if引导的真实条件状语从句

表示如果条件成立，就会发生某种结果，通常遵循"主将从现"原则：主句用一般将来时，从句用一般现在时。

基本结构：If + 一般现在时从句, 一般将来时主句

If it rains tomorrow, we will stay at home. 如果明天下雨，我们就待在家里。

If you study hard, you will pass the exam. 如果你努力学习，你就会通过考试。

I will go to the park if I have time tomorrow. 如果我明天有时间，我就去公园。

常用情态动词代替will：当主句表示建议、许可、能力等时，可以用can, may, must等情态动词代替will

If you finish your homework, you can watch TV. 如果你完成了作业，你可以看电视。

If you want to go abroad, you must have a passport. 如果你想出国，你必须有护照。

If you have any questions, you may ask the teacher. 如果你有任何问题，你可以问老师。

祈使句 + and/or + 简单句：相当于条件状语从句

Study hard, and you will pass the exam. = If you study hard, you will pass the exam. 努力学习，你就会通过考试。

Hurry up, or you will be late. = If you don't hurry up, you will be late. 快点，否则你会迟到的。

2. if引导的宾语从句

if也可以引导宾语从句，表示"是否"，相当于whether，通常放在动词know, ask, wonder, find out等后面。

基本结构：主句 + if + 陈述句

I don't know if he will come tomorrow. 我不知道他明天是否会来。

She asked if I had finished my homework. 她问我是否已经完成了作业。

I wonder if it is going to rain. 我想知道是不是要下雨了。

类型	含义	时态规则	例句
条件状语从句	如果	主将从现	If it rains, I will stay at home. 如果下雨，我就待在家里。
宾语从句	是否	时态呼应	I don't know if it will rain tomorrow. 我不知道明天是否会下雨。

3. 情态动词用法总结

情态动词表示说话人的语气和情态，没有人称和数的变化，后面接动词原形，否定句直接加not，疑问句将情态动词提前。

情态动词	含义	用法	例句
can	能力	表示有能力做某事	I can swim. 我会游泳。
	许可	表示允许做某事	You can go now. 你现在可以走了。
	可能性	表示理论上的可能性	It can be very hot in summer. 夏天可能会很热。
may	许可	正式的请求或允许	May I come in? 我可以进来吗？
may	可能性	表示实际的可能性	It may rain tomorrow. 明天可能会下雨。
must	义务	表示必须做某事	You must finish your homework first. 你必须先完成作业。
	肯定推测	表示非常肯定的推测	He must be at home. 他肯定在家。
	禁止	mustn't表示禁止	You mustn't smoke here. 你不许在这里抽烟。
need	需要	表示需要做某事（否定needn't表示不必）	You needn't come tomorrow. 你明天不必来。
should	应该	表示建议或义务	You should see a doctor. 你应该去看医生。
had better	最好	表示强烈的建议	You had better go now. 你最好现在就走。

情态动词表推测：

must 表示肯定推测（90%以上的把握）：He must be tired. 他肯定累了。

may/might/could 表示可能推测（50%左右的把握）：He may be at home. 他可能在家。

can't/couldn't 表示否定推测（90%以上的把握不可能）：He can't be at home. 他不可能在家。

4. 反意疑问句

反意疑问句由两部分组成：前一部分是一个陈述句，后一部分是一个简短的疑问句，两部分的人称时态应保持一致。遵循"前肯后否，前否后肯"的原则。

基本结构：陈述句, 简短问句？

You are a student, aren't you? 你是学生，对吗？

He likes playing football, doesn't he? 他喜欢踢足球，不是吗？

She can speak English, can't she? 她会说英语，对吗？

They will come tomorrow, won't they? 他们明天会来，不是吗？

前否后肯：

You aren't a student, are you? 你不是学生，对吗？

He doesn't like playing football, does he? 他不喜欢踢足球，是吗？

She can't speak English, can she? 她不会说英语，对吗？

特殊情况：

There is a book on the desk, isn't there? 桌子上有一本书，对吗？

Let's go to the park, shall we? 我们去公园吧，好吗？

Open the door, will you? 打开门，好吗？

I am late, aren't I? 我迟到了，对吗？

回答：反意疑问句的回答根据事实来定，事实是肯定的用yes，否定的用no

- You are a student, aren't you? 你是学生，对吗？
- Yes, I am. / No, I'm not. 是的，我是。/ 不，我不是。

- You aren't a student, are you? 你不是学生，对吗？
- Yes, I am. / No, I'm not. 不，我是。/ 是的，我不是。

5. 打电话常用表达

接电话时：

Hello, this is John speaking. 你好，我是约翰。

Who's that speaking? 请问您是哪位？

Is that Tom? 你是汤姆吗？

打电话时：

May I speak to Tom? 我可以和汤姆讲话吗？

Can I leave a message? 我可以留个口信吗？

Hold on, please. 请稍等。

打错电话时：

I'm sorry, I think I have dialed the wrong number. 对不起，我想我拨错号码了。

It doesn't matter. 没关系。

配套练习

练习一：用所给动词的适当形式填空（if条件状语从句）

1. If it ______ (rain) tomorrow, we ______ (stay) at home.

2. If you ______ (study) hard, you ______ (pass) the exam.

3. I ______ (buy) a new bike if I ______ (have) enough money.

4. If he ______ (come) to see me, I ______ (be) very happy.

5. You ______ (can go) out if you ______ (finish) your homework.

1. rains, will stay 2. study, will pass 3. will buy, have 4. comes, will be 5. can go, finish

练习二：选择if的正确含义（如果/是否）

1. I don't know if he will come tomorrow. ( )

2. If he comes tomorrow, I will tell you. ( )

3. She asked if I had finished the work. ( )

4. If you don't hurry up, you will be late. ( )

5. I wonder if it is going to rain. ( )

1. 是否 2. 如果 3. 是否 4. 如果 5. 是否

练习三：完成下列反意疑问句

1. You are from China, ______?

2. He likes playing basketball, ______?

3. She can swim, ______?

4. They will go to the park tomorrow, ______?

5. He isn't a doctor, ______?

6. Let's go shopping, ______?

7. Open the window, ______?

8. There is a cat under the tree, ______?

1. aren't you 2. doesn't he 3. can't she 4. won't they 5. is he 6. shall we 7. will you 8. isn't there

练习四：选择合适的情态动词填空（can, may, must, need, should）

1. ______ I come in? Yes, please.

2. You ______ finish your homework first before watching TV.

3. He ______ speak three languages.

4. You ______ see a doctor if you don't feel well.

5. You ______ worry about me. I'm fine.

6. It ______ rain tomorrow, so take an umbrella with you.

1. May 2. must 3. can 4. should 5. needn't 6. may

练习五：翻译下列句子

1. 如果明天天气好，我们就去公园。

2. 我不知道他明天是否会来。

3. 你是学生，对吗？

4. 你必须在十点之前回家。

5. 如果你努力学习，你就能通过考试。

1. If it is fine tomorrow, we will go to the park.

2. I don't know if he will come tomorrow.

3. You are a student, aren't you?

4. You must go home before ten o'clock.

5. If you study hard, you can pass the exam.