Grammar and usage(1): Modal verbs: general introduction教学评价实录

情态动词教学设计

Step 1:Lead-in: As College Entrance Examination is coming, they must be very tired and exhausted. Step 2: Definition of modal verb:情态动词主要用以说明说话者对某一行为的态度和观点，主要包括许可、判断、意愿和推测。

Step 3: Characteristics of modal verb: 1.情态动词不能单独作谓语动词，必须和实义动词或连系动词连用，构成谓语。

2.情态动词除have to外没有人称和数的变化。

3.有些情态动词没有过去式，如must；有些有过去式，如：can-could

may-might

shall- should

will- would

4. 情态动词的过去式有时可能并不表示过去，而只是表示一种特定的语气（如使委婉等）

Step 4: usages of modal verb 一、can 与could 的用法

1.

表示能力

My mother likes to keep up with fashion, so she can use We Chat to chat with me. At the Nathan's Famous hot dog eating competition, a man from Japan could eat 53 hot dogs in 12 minutes. Attention：can/ be able to的区别

can 只有现在时和过去时could, 而be able to 则有更多的时态变化，在将来时、完成时和非谓语动词中只能用be able to。

can一般指自身具有的能力，而

be able to 则表示有能力并且得以成功做成，相当于manage to do 或succeed in doing。

2.

表示请求和许可（多用于口语）

Can/Could you show me the way to the bus station? Attention: 在表示请求的口语中常用could 代替can, 语气更加委婉，但回答只能用can. 3.

推测，通常用于否定句和疑问句中，can’t / can not译为“不可能”

—Listen. Someone is knocking at the door! Who ____ it be? —_____it be David? —No, it _____be him. He has gone to Shang Hai. 4.

Can 用在肯定句时，表达“理论上的可能性”，即事件或情况可能发生，但并不涉及是否真的会发生。有时指一时的情况，常常译为“有时会”。

1.Children are lovely, but they can be annoying sometimes. 2.Everyone can make mistakes. 5.

惊讶、怀疑、不相信的态度（主要用于否定句、疑问句或感叹句中）。

How can you be so rude to your girlfriend in public ! 6.

习惯用法“ cannot/ can never…too/enough…” 表示:无论怎样……都不过分或越……越好。

You can never be too careful to cross the road. Uncle Wang is a genius cook and we _______ never get enough of his cookies. 二、may 与might 的用法

1. 表示许可或征求许可，译为“可以”

—Mum, may I watch TV after supper? —Yes, you may/can. —No, you mustn’t /can’t / may not.

2.

表示“可能，也许”。推测，通常用于肯定句和否定句，不用于疑问句，一般在不确定的情况下使用，may not 译为“可能不”

Joan_____ come with us this afternoon, but she isn’t very sure yet.

A.

can

B. may

C. must

D. will 3.

表示祈使句中表示祝愿。

May you succeed! 4.

May/ might as well 表示有礼貌的劝告，常译为“还是……的好，不妨……”.

It’s too late. You might as well not go.

5.

may well do sth.表示“很可能做某事”

This ring may well be a fake. 三、will与would 的用法

1.表示意志、意愿和决心。用于各种人称，will指现在，would指过去

I reasoned with you about drunk driving many times, but you _______ listen. I _____ never do such a thing again. 2.

表示请求、建议。用于第二人称的疑问句，would表更委婉的语气。

1.Will you call back later, please? 2.Would you mind opening the window for me? 3. 表示习惯性的动作，意思是“总是；习惯于”。will指现在，would指过去。

1.Fish will die without water. 2.She would sit there for hours, reading a book.

would/used to的区别

would 表示过去的习惯性动作（不表状态），现在有可能还如此，也可能不再那样。

used to 既表示过去的动作也表示过去的状态，不过现在不再做或不再有那种状态了。

4.表示事物的功能属性，趋向性

The door _____________ though I have tried several times. I wanted to enter the room, but the dog________ let me in. 四、shall 与should的用法

1. shall第一、第三人称的疑问句中，表示说话人征求对方的意见或向对方请求。

1.What shall we do this evening? 2.Shall he be able to leave the hospital? 2. shall第二、第三人称，表示说话人给对方命令、警告、允诺或威胁。

1.You shall fail if you don’t work hard. 2.He shall have the book when I finish reading it. 3.You shall not leave your post. 3. shall第三人称，在条约、规定、法令等文件中表示义务或规定，意为“必须”。

The school rules state that no student shall be allowed out of the school during the day. 4. Should为shall 的过去式，表示义务，责任，劝告或建议，意为“应该”。

用于表示建议、命令的动词suggest，advise，require，demand，request，insist 等。

1.He suggested that I should accept the job. 2.My teacher demanded that we should finish our homework on time. 5. should根据时间，惯例，常理推测，意为“照理说，应该会，理应”

Li lei’s sister _______be around 10 years old.

I wonder if I can board the plane with this return ticket. There ______ be no problem. Your ticket is valid until the end of this month.

6.

should惊讶，意为“难以置信，竟然”

The men should be so rude to the girl. 7. 用于if 条件虚拟语气中，意为“万一”

This printer is of good quality. If it ________ break down within the first year, we would repair it at our expense. 8. ought to的用法

表示责任和义务，意为“应该”，与should 同义，只是语气重一些。如要反映客观情况或涉及法律义务和规定时一般用ought to。

五、must 的用法

1. 表示“必须”，其否定形式为mustn’t。（不准，禁止）

Everybody must obey the law. You mustn’t drive so fast in the street.

2.以must开头的一般疑问句的肯定回答中要用must，否定回答中要用needn’t/ don’t have to，而不用mustn’t。

— Must I finish the paper today? —Yes, you ___. —No, you________. 用must或have to填空：

I _______

go now, for my mother is ill. I ________stop smoking. They __________buy a computer at present. The magazine ________be taken out of the reading room. 3.

表示有把握的肯定推测，只能用在肯定句中，意思是“一定；准是”，在否定句，疑问句中要用can’t代替。

1.He must be working in the office. 2.It _____be her. I’m sure that she doesn’t wear glasses.

4. 表示感情色彩，意为“偏偏；偏要；一定要”，常指令人不快的事情。(条件句和疑问句中) 1. I’m sleeping now. Must you make so much noise?

2.— Can I borrow your car, mum?

— If you_____. 六、可兼做行为动词的情态动词：need、dare

dare:做情态动词，不用于肯定句

做实义动词，dare to do need:做情态动词，不用于肯定句

做实义动词，need to do didn’t need to do

needn’t have done

I forgot to take an umbrella when I went camping last weekend. You ____________. The weather forecast didn’t say it was going to rain.

I took an umbrella when I went camping last weekend. You ___________. The weather forecast didn’t say it was going to rain.

判断正误题：

How dare you say such a thing?

How dare you to say such a thing? He daren’t to speak English before such a crowd, did he?

He daren’t speak English before such a crowd, dare he? Nobody need to be afraid of catching the disease. Nobody need be afraid of catching the disease. These dishes needed be cleaned carefully. These dishes need to be cleaned carefully. These dishes need cleaning carefully “情态动词+have done”用法

must have done

表示主观上对过去已经发生的行为进行推测，意为“想必，准是，一定做了某事”

注：无

mustn’t have done

may/might（not）

have done

表示对过去已发生行为的推测，意为“也许/或许已经（没有）……“。一般用于肯定句或否定句中，不用于疑问句。用might则表示语气更加不肯定。

could have done

cannot/couldn’t have done

Can /could… have done sth.?

表示对过去发生的行为的怀疑和不肯定，can通常用在否定句和疑问句中。（can换成could时语气委婉）

could have done

本能够、本可以做，但没做成，有一种对过去未付诸实施的事情的惋惜。

might have done

表示“本来可能……，但实际上没有发生的事情”。另外，还可以表示“本来可以做某事”之意，含有轻微的责备语气。

should/ought to have done

用于肯定句时，表示本该做某事，而实际上未做；用于否定句时，则表示本不该做的事反而做了。

needn’t have done

表示做了本来不必去做的事。

Step 5：

Consolidation