(共39张PPT)
Unit 6
Electricity
Oxford English
Module 3 Natural elements
Grammar
Modal verbs
情态动词
Do you know
“Modal verb”
Warming-up
may (might)
can (could)
need
ought to
shall (should)
must
( Modal verbs)本身有一定的词义,表示语气的单词。但是不能独立作谓语,只能和动词原形一起构成谓语.情态动词用在行为动词前,表示说话人对这一动作或状态的看法或主观设想.
情态动词
will(would)
dare
情态动词没有人称和数的变化。
情态动词不能单独作谓语动词，只能与动词原形一起做谓语，没有人称和数的变化。
A bird can fly .
Fish can't live without water.
You must hand in your homework at once.
You mustn't talk loudly in public.
can/could
may/might
must
shall/should
will/would
need
have to
能够
可能
必须
应该
意愿
需要
不得不
+ 动词原形
情态动词表示说话人对某一动作或状态的态度，可表示“可能”、“可以”、“需要”、“必须”或“应当”等之意。
肯定 否定 缩写否定
can can not can’t
could could not couldn’t
may may not /
might might not mightn’t
must must not mustn’t
should should not shouldn’t
need need not needn’t
can/can't
may/may not
must/must not
本课重点
情态动词
He can play football and
speak two languages.
But he can't cook or
play chess.
can的用法
and 肯定句；or否定句
I can dance well.
Can you
No, I can't. But
I can swim well.
Can you
can的用法
We use can and cannot(can’t) to say we are able or not able to do things.
We can use electricity to do many things.
We cannot(can't)electricity.
Can you think of an example
Yes, I can./ No, I cannot(can't).
can的用法
用法总结:
1.can表示__________.
2.can 后面动词用________.
3. can的否定形式是：_______或________.
4. 一般疑问句是将can_______.
有能力做某事
原形
can't
cannot
提前
can and cannot
My elder brother _________(能) drive a car.
否定句：
一般疑问句：
肯定回答：
否定回答：
就划线部分提问：
can
My elder brother cannot/can’t drive a car.
Can your elder brother drive a car
Yes, he can.
No, he can’t.
What can your elder brother do
2.表示推测，意为“可能”，常用于否定句和疑问句中，此时can’t译为“不可能”。
—Can it be Mary 会是玛丽吗？
—No, it can’t be her. She has gone to Shanghai on business. 不可能是她。她去上海出差了。
can/could的其他用法：
1.could用来表示请求许可时，语气委婉，主要用于疑问句，不能用于肯定句，答语应用can（即：could不能用于现在时态的简略答语中）。
如：--Could I use your dictionary
--Yes, you can.
(否定回答可用：No, I'm afraid not.或者是you can't)
could&can
1.could是can的过去式，意为“能；会”，表示过去的能力。
He could play the piano when he was 5.
当他5岁时，他就会弹钢琴了。
2.在表示请求许可时，can，could没有时态区别，只是could在语气上更加委婉客气。
—Could I use your dictionary 我可以用你的字典吗？—Yes, you can. 可以。
注意：
Hi and Lo are talking about themselves. What are they saying Read their conversation and then complete the statements below with Can or Cannot.
1. Hi _____ play football.
2. Lo _______ paint.
3. Hi _______ speak as many languages as Lo.
4. Both Hi and Lo _____ dance.
5. Lo ______ drive a car, but he ____ play chess.
6. Hi ____ swim, but he _______ play the guitar.
can
can
can
can
cannot
cannot
cannot
cannot
Yes, you may/can.
May/Can I sit down
may的用法
___________I come in
Yes,you may/can.
No, you may not /can't.
May/Can
may的用法
We use may and may not to ask for and Give permission(许可). We also use can and cannot (can’t) for the same purpose.
May/Can I use you mobile phone
Yes, you may/can.
No,you may not/can't.
may的用法
观察：
总结：
1：can/may表示：____和_____.后接:_____
2: can的否定形式:____________
may 的否定形式：________
May/Can I use your mobile phone？
Yes, you may/can.
No, you may not/can't.
You may/can turn on the TV.
You may not/cannot play in the kitchen.
请求
允许
原形
can't/cannot
may not
You __________ (可以) leave now.
否定句：
一般疑问句：
肯定回答：
否定回答：
就划线部分提问：
may
You may not leave now.
May I leave now
Yes, you may.
No, you may not.
When may I leave
2.may的过去式为might，表示推测时两者无时态区别，不过might的可能性低于may。
He might be sick.他可能是生病了。
1.may还可表示推测，谈论可能性，意为“可能；或许”，一般用于肯定句中。
It may rain tomorrow. 明天可能会下雨。
注意：
may&might
3.表示希望、祈求、祝愿时，may常译为“祝愿”，通常结构为“may+主+v.”。
May you have a good time！祝你玩得开心！
Daisy is not feeling well today. Benny is at home with her. Read their conversation below. Fill the blanks with may or can.
Benny: Yes. I ____. _____ I carry your bag for you
Daisy: Yes, you may. That’s so kind of you, Benny. I’m
ready to go. _____ you open the door for me
Benny: Yes, I can.
Daisy: Thanks.
May
can
Can
Benny: How are you feeling, Daisy
Daisy: Not very well.
Benny: ____________ I get you a chair
Daisy: Yes, thanks.
Benny: I’m going out. _____ I borrow your bicycle,
Daisy
Daisy: Yes, you may. Before you go to meet your friends, can you come and see the doctor with me
May
May/Can
What do these signs mean
You mustn’t smoke here.
You mustn’t climb this ladder.
You mustn’t swim here.
You mustn’t use your mobile phone here.
must的用法
Must you do
homework now
Yes, I must. Must you do your homework
No, I needn’t.
must的用法
No, I don't have to.
We use must and must not (mustn’t) to tell people what to do or what not to do.
You must not/mustn't do that Benny!
We must always be careful with electricity.
They must not/mustn't play near the heater.
must的用法
观察：
总结：
1. must表示______和_______.后接_____
2. Must 提问，肯定回答：仍用______回答
否定回答：用___________或_________
1.We must listen to Miss Li carefully.
2. You must not/ mustn't be late for class.
3. Must I clean the blackboard now
Yes, you must.
No, you needn't. No, you don't have to.
命令
禁止
原形
must
you needn't
you don't have to
Lily__________ (必须) go to the library.
否定句：
一般疑问句：
肯定回答：
否定回答：
就划线部分提问：
must
Lily mustn't go to the library.
Must Lily go to the library
Yes, she must.
No, she needn’t./doesn't have to.
Where must Lily go
1.must意为“必须；一定”。must的否定形式mustn’t 意为“一定不要；千万别”或“禁止；不许”。
You mustn’t make noise in the library.
你一定不要在图书馆吵闹。
注意：
must&mustn't
2.must表示很有把握的推测，意为“一定会；肯定会”，只用于肯定句。
He won the prize in the English competition. His English must be very good.
他在英语竞赛中获奖了。他英语一定很好。
Daisy saw a doctor. The doctor told her what to do and what not to do. Help her write down the doctor’s instructions.
drink more water go to bed early
eat cold food share cups with others
go out alone take the medicine on time
I must drink more water.
______________________________
______________________________
I must not _____________________
______________________________
______________________________
I must go to bed early.
I must take the medicine on time.
eat cold food.
I must not go out alone.
I must not share cups with others.
观察：
1. He may be Tom. Because he looks as tall as Tom.
But I am not sure.
2. -Can the story be true
-It can't be true. He lied.
3. He must be at home. Look! The lights are on.
总结：
1.can/may/must还可以用来表示_________.
2.可能性由大到小的排序：________________.
3. must表示一定，其“不可能”是：__________
4. 表示可能时，________不用于肯定句。
推测
must---may/can
can't
can
注意：
may&can&must的双面性
Modal Verbs
情态动词两要点
动词原形跟后面
说话语气较委婉
can能力may许可
must责任或义务
否定回答needn't换
should应该,would愿
have to 被迫表客观.
【记忆口诀】
（2016 福州）
--Look at the young lady in red．Is it Mrs．King？
--No，It ________ be her．She is wearing a white dress today．
A．can B．may
C．must D．can't
中考链接
（2016 绵阳）
--Is Mr Brown driving here？
--I'm not sure．He ______ come by train．
A．may B．shall
C．need D．must
（2016 滨州）
--Must I go to law school and be a lawyer like you，Dad？
--No，you _____，son．You're free to make your own decision．
A．can't B．mustn't
C．shouldn't D．needn't
