Welcome to the unit教学设计一等奖

情态动词教学案

主要考查的知识点：

(1)情态动词的基本用法

(2)情态动词＋完成式的用法

(3)情态动词的一些特定用法

学习重点：

(1)情态动词的意义以及不同的情态动词的用法区别

(2)must, can, should等常见情态动词的用法

(3)must/ can/ should/ might＋have done的用法及区别

(4)含情态动词的疑问句的回答

情态动词的基本用法

情态动词表示说话人的语气和情绪，本身词义不全，不能单独作谓语，必须与后面的动词原形一起构成谓语。情态动词没有人称和数的变化，有的情态动词有过去式。常见的情态动词有can, could, may, might, must, have to, shall, should, will, would, ought to, need, dare, used to

1.

can /could 的用法

1) 表示能力

The parrot can speak three languages. 2) 表示允许

过去式could常用于疑问句中, 比can更加委婉, 表示礼貌。肯定回答时, 常用原形can或者may, 不可再用过去式could。

---Could I use your pen? (语气委婉) ---Yes, you can.

----No, you can’t /mustn’t. 3) 在肯定句中, can还可表示“有时会”

Growing up can be very difficult

The World Wide Web is sometimes jokingly called the World Wide Wait because it ___be very slow.

A. should

B. must

C. will

D. can 用于肯定句中常常表示理论上的可能性，用来表达事件或情况可能发生(但并不牵涉到是否真的会发生)。

4)

can’t….too / enough / comparative degree 无论怎样……也不算过分，用来加强语气

e.g

You can’t be too careful while crossing the street

You can’t find a better present for me.

I can’t thank him enough

5)

表示推测

( 只能用在否定句或疑问句中。)

e.g.

It’s so late. Can Tom be reading?

He can’t be in the office now, for the light is off

Couldn’t have done 对过去发生行为的可能性进行推测:

e.g.

I saw him just now so he couldn’t have gone abroad. 6) /could have done “本可以，本来可能已经”用于肯定句中，表示对过去发生的事情做出的判断.

You could have gained higher scores, but you were so careless 7)其它用法

(1)

can’t help it / can’t help doing /can’t but do

e.g.

If I can help it, I didn’t want to work late (如果我有办法的话，我也不喜欢工作地太晚) 8) 注意

can, could 和be able to的用法

(1) .can只用于现在时和过去时(could)。

be

able

to可以用于各种时态

We’ll be able to finish the work soon.

I haven’t been able to see the film

(2) could仅表示过去具备某种能力, 而

was/were able to表示不仅具备而且实施了某种能力;更侧重于“克服一定困难, 经过一定努力做成某事”

He

was

able

to

escape from

Europe

before

the

war

broke

out.

He

was

able

to

swim

before

he

got

tired.

2. may/might的用法

1) 表示推测时，只能用于陈述句，表示对现在或将来要发生的动作把握不大

They may come here tomorrow

They may be still waiting for us. 2) might 可用于表示可能性更小。

He might be doing his homework now 3) .might/may have done,表示对过去发生的动作进行可能性推测。

He might have read about the news in the newspaper

4）may /might 表示许可，

①might, 比较委婉, 一般多用于疑问句; ②在以could, might表示征询对方意见或表示请求时, 回答应相应使用can, may; ③表示允许(肯定句)和请求(疑问句)若回答表示

“不可以/不准”

时, 一般用mustn’t

---May/Might I use your dictionary? ---Yes, you may/can.// No, you mustn’t 5）

May 用于祈使句，表示祝愿。

May you succeed!

May you have a nice trip!

6)

may well

“极有可能”

Liza may well not want to go on the trip --- she hates traveling. 7)

may/ might as well

“不妨”

If the ticket for today is not available, I might as well take the ticket for tomorrow

3. shall

的用法

1) 用于第一、三人称的一般疑问句中

表示说话人征求对方的意见和向对方请示。

Shall we begin our class?

A: A Mr. White wants to see you. Shall he come in or wait outside?

B: Just let him in

2)

shall

用于第二，表示说话人给对方的命令，警告，允诺或威胁。

You shall go with me.(命令)

You shall have the book when I finish it.(允诺)

3) 用于条约，规定，规章等文件中，表示一种义务，多用于第三人称中。

Each competitor shall wear a number. 每个参赛者要戴一个号码

The interest ___be divided into five parts, according to the agreement made by both sides.” declared the judge.

A. may

B. should

C. must

D. shall

4. should 的用法

1) 用于表达合理推断

It is three o’clock, the football game should begin now.

Mary took dancing lessons for years, she should be an excellent dancer.

2) should可表示“居然，竟然”。

I can’t believe that such a gentleman should be so rude to the old.

.我不敢相信这样一个绅士居然对老人

如此无礼。

3) should常表示劝告、建议、命令

,要求

(1)

suggest/ advise / ask/demand/require/recommend/ insist/hold/ order that主语+should + 动词原形

(2)

It’s strange / surprising /necessary /important / vital / essential that

4) should 用在与将来事实相反的虚

Should it break down within the first year, we would repair it at our expense

5) should/ought to have done表示责备或批评,意为“本应该做到…但没有做到…”,用于否定则表示“本不该…

You should/ought to have told her the truth earlier.

She shouldn’t have left without saying a word.

5. Must的用法

1) 表示对现在的肯定推测must do (状态动词, 如: live/have/know),

must be (doing)

表示对过去的肯定推测

must have done

Practice :你现在一定困了。_______________________________________

他昨晚一定看足球比赛了___________________________________________

You must be sleepy now, aren’t you?

He must have watched film last night, __________?

He must have watched film, _____________? 2)

mustn’t 表示“禁止、不准”

3)

Must 、have to 与have got to

Must 指说话人认为“主观”上有必要

have to: 指根据约定, 指说话人认为做某事有“客观”必要

The train leaves at 7 o’clock. I ___________ (must / have to) go now

I don’t like my watch. I _______(must / have to) buy a new one. 4) 在疑问句中“must”表示“必须”的回答形式

肯定

“Yes, sb. must.”;

否定

“No, sb. needn’t.”

或“No, sb. don’t (doesn’t) have to.”

don’t have to = needn’t 没必要

---- Must you go home now? (必须)

---Yes, I must./ No, I needn’t. =I don’t have to 5)

must有时表示“偏要”,含“责备,抱怨”之意

Practice

我已经跟你讲过很多遍了, 为什么你偏要

在课堂上讲话呢？

________________________________________________________________

现在已是午夜了, 你偏要这个时候弹钢琴吗？

_________________________________________________________________ 6)

“if you must do…”可以看作是固定句式，意为“如果你非……不可的话”，常用来表示在不十分同意或赞成的情况下，允许某人干某事或责备对方没有礼貌。如：

--- Who is the girl standing over there？站在那边的女孩是谁？

---Well, if you must know, her name is Mabel. 如果你一定要知道的话，（我就告诉你吧），她的名字是梅布尔。（句中if you must know表示“如果你一定要或坚持要知道的话”，含“勉强同意”之意）。

6. Will/ would 的用法

1)

will (would) 表决心、愿望。

would 为

will 的过去式, 可用于各人称。

I'll do my best to catch up with them.

我要尽全力赶上他们。

I'll never do it again, that's the last time.

我再不会做那件事情了,这是最后一次。

2) will, would用于疑问句表示说话人向对方提出请求或询问,用

would 比

will 更婉转,客气。

It's hot. Will you open the windows?

天气太热了,你能打开窗户吗?

Will you help me to work it out?

你能帮我解这道题吗?

3) 表示习惯性、经常性、倾向性，意为“总是”，“惯于”。

will指现在，would是指过去，如：(2)。

He’s strange -- he ____ sit for hours without saying anything.

A. shall

B. will

C. can

D. must

分析：will用来谈习惯和特性，尤其是不受时限必然发生的情况。本句意思为“他很怪，能一坐几个小时一句话也不说”。答案为B。

4) won't表示失去某种功能或属性，

The door won’t shut

Take care! Don’t drop the ink on your shirt, for it ________

A. won’t wash out

B. won’t be washed out

C. isn’t washed out

D. isn’t washing out 5) would 与used to 的区别：

①used to 强调今昔对比，过去的某种习惯，现在已经没有了；would 表示过去一段时间里有某种习惯，现在可能还有。试比较：

We would sit in the yard every evening and listen to his story. (过去会这样，现在可能还这样)

We used to sit in the yard every evening and listen to his story. (过去会这样，但现在不这样了) ②

表示过去的状态，只能用used to，不能用would，

There used to be a park here.

7. need的用法

1) need作情态动词表示“需要”“必要”。通常用于否定句、疑问句、条件句中，且只有现在时，其他时态用“have to”的相应形式代替

2)

对于Need …？

的肯定回答用

… must。

— Need I go there right now?

— Yes, you must.

3) needn’t have done 表示

3) need用作行为动词，其变化与行为动词相同。若主语为动作承受者时，用动名词的主动形式表示被动意义，或用不定式的被动形式，如：

The house needs repairing.＝The house needs to be repaired. 4)

needn't have done表示“本来不必做而实际上做了的事情”

You needn't have come over yourself.

dare的用法

(1)dare作情态动词表示“敢于”，可用于否定句、疑问句和条件句中，

如：No one dared speak of it. (2)用作行为动词，其变化与一般动词相同，在疑问句中时，dare后的“to＋动词原形”可以省略to，如：Do you dare (to) jump into the ocean? (3) 惯用短语“I dare say”意为“我想，大概”。

The queen replied, "I dare say you haven't had much practice. When I was your age, I always did it for half an hour a day