(共41张PPT)
Unit 3
Could you please clean your room
enjoy dinner with my family.
A: Mum, could I go out for dinner with my
friends
B: Sure, that should be OK.
A: Could I get something to drink with my
friends after the movie
B: Sure, you can.
A: Could I get something to drink with my
friends after the movie
B: No, you can’t, you have a basketball game
tomorrow.
take the dog for a walk
遛狗
A: Can you please take the dog for a walk
B: OK, but I want to watch one show first.
take out the rubbish
扔垃圾
A: Can you please take out the rubbish
B: Yes, sure.
Could I go out for dinner with my friends
Sure, that should be OK.
Could we get something to drink after the movie
No, you can’t, you have a basketball game tomorrow.
Grammar Focus
Can you please take the dog for a walk
OK, but I want to watch one show first.
Can you please take out the rubbish
Yes, sure.
只作情态动词的 can / could, may /
might, ought to, must
可情态可实义的 need, dare
可情态可助动词的 shall / should, will /
would
相当于情态动词的 have to, used to
情态动词的语法特征
1) 情态动词不能单独做谓语, 除ought和have外, 后面只能接不带to的不定式。
2) 情态动词没有人称, 数的变化, 但有些情态动词, 如can、will也有一般式和过去式的变化。
3) 情态动词的“时态”形式并不是时间区别的主要标志, 不少情况下, 情态动词的现在式形式和过去式形式都可用来表示现在时间、过去时间和将来时间。
1) can的主要用法是：
A. 表示体力或脑力的能力：
e.g. The girl can dance very well.
B. 表示说话的推测﹑事物的可能性等:
e.g. Can the news be true
C. 在口语中, can可以表示请求或允许:
e.g. Can I sit here
can 和could：
can表示“能够”时与短语be able to同义，但can只用于一般现在时或过去时，而后者可用于各种时态。另外，can表示个人有某种能力，而be able to表示某人通过努力、克服困难做成某事，相当于succeed in doing sth.；叙述过去事实时，最好用was / were able to，因为could只表示过去具有某种能力。
例如：
Can you understand the different kinds of English these people are using
Two years later, he was able to speak very good Chinese.
2) could的主要用法是：
A. could 是can的过去式, 表示与过去 有关的能力和推测:
e.g. We all knew that the young man
couldn’t be a doctor.
B. could可以代替can表示请求, 但语气较can客气、委婉:
e.g. Could you lend me your
dictionary
Could I use your bike
3) can和could接动词的完成形式，表示可能已经做某事。can用在否定和疑问句中, 表示不相信、怀疑等态度。
e.g. They can’t have gone out because the light is still on.
以could或would提问时，不能再以could或would作答，而应该用can或will。如：
—Could I borrow your dictionary
—Yes, of course you can.
情态动词用法小结
1. 情态动词不能表示正在发生或已经发生的事情, 只表示期待或估计某事的发生。
2. 情态动词除ought 和have 外, 后面只能接不带to 的不定式。
3. 情态动词没有人称，数的变化，即情态动词第三人称单数不加-s。
4. 情态动词没有非谓语形式，即没有不定式、分词等形式。
could与can的区别
could与can都是情态动词, could是can的过去式。二者都可用于表示请求, 但是用法稍有不同。
can 表示一般性的请求，语气随便, 常用于
熟人之间或长辈对晚辈, 上级对下级的
场合。
e.g. Can you tell us your story, Tony
Tony，你能给我们讲讲你的故事吗？
could表示有礼貌的请求，语气委婉，
常用于非熟人之间或晚辈对长辈，下级
对上级的场合。例如：
--Could you tell us if it snows in winter in
Australia
--Sure.
——请告诉我们, 澳大利亚冬天下雪吗
——当然可以。
注意：
1. 提出委婉的请求在回答中不可用could。
A: Could I have the television on
B: Yes, you can. / No, you can’t.
2. 在否定、疑问句中表示推测或怀疑用 couldn’t。
He couldn’t be a bad man.
他不大可能是坏人。
两词都是 “必须”的意思, have to 表示
客观的需要, must 表示说话人主观上的
看法, 既主观上的必要。
have to和must
may和might
表示允许或请求; 表示没有把握的推测; may放在句首, 表示祝愿。
May God bless you!
He might be at home.
注意: might 表示推测时, 不表示时态，只是可能性比may小。
My brother was very ill, so I had to
call the doctor in the middle of the night.
我弟弟病得很厉害，我只得半夜里
把医生请来。(客观上需要做这件事)
He said that they must work hard.
他说他们必须努力工作。
(主观上要做这件事)
2. have to 有人称、数、时态的变化,而must只有一种形式。但must 可用于间接引语中表示过去的必要或义务。
He had to look after his sister yesterday.
3. 在否定结构中: don’t have to 表示 “不必”, mustn’t 表示“禁止”。
You don’t have to tell him about it. 你不一定要把此事告诉他。
You mustn’t tell him about it. 你一定不要把这件事告诉他。
4a Write R for requests and P for permissions. Then match each one with
the correct response.
_____ Could I hang out with my friends
after the movie
2. ____Could you please pass me the salt
3.____Could I borrow that book
4.____Could you help me do the dishes
5.____Could you lend me some money
P
R
P
R
R
Yes, here you are.
Hmm. How much do you need
Yes, sure. No problem. I finished reading
it last night.
d. Yes, but don’t come back too late.
e. No, I can't I cut my finger and I’m trying
not to get it wet.
1—d 2—a 3—c 4—e 5—b
4b Fill in the blanks in the conversation
A: I hate to_________ chores.
B: Well, I hate some chores too, but I like
other chores.
A: Really Great! ________I ask you to____
me with some chores then
B: What do you need help with
A: ______ you please _____my clothes for me
B: I don’t want to do that! It’s boring!
Could
do
help
Could
fold
A: OK. Then______ you ______do the dishes
for me
B: Sure, no problem. But_______ we go to
the movies after that
A: Sure, I’ll finish my homework while you help me with the dishes. Then we can go to the movies.
could
please
could
4c Make a list of things your group needs to
do for a camping trip. Then discuss who will
do bring a tent them and complete the chart.
A: Could you please bring Liu Chang
B: Sure. And could you please …
C: Sorry, I can’t. I have to…
To—do list Name
Bring a tent Liu Chang
Pair work
用情态动词can/could, can’t, may,
must, mustn’t , needn’t填空。
1. - _____ you come and play with us now
- I’m afraid I _____. I _____ do the cooking. I ____ come later.
2. - _____ we clean the windows today
- No, you _______. You ____ clean them tomorrow.
Could
can’t
must
can
Must
needn’t
can
3. - ____ I watch TV this evening, mum
- No, you _______. Work _____ come first.
4. - ____ I come in, please
-Yes, please.
5. Excuse me. ____ you tell me the way to the cinema
May
mustn’t
must
Can
Can
A: Could you help me, please
B: ___________!
A: I want to ________these boxes to my home
Let’s ______ the boxes _____ the car now.
B: _______right.
A: Oh, the box ___ heavy. Can you carry it
B: Yes, I______
A: ________you _____ it to my room
B: Certainly.
完成对话
Certainly
take
put
in
All
is
can
Could
take
can; could
When I was young I _____ climb any tree in the forest.
Learning a language _____ be a real challenge.
could
can
选用正确的情态动词填空。
这个暑假你与父母要去法国去度假， 你的宠物小猫Mimi需要请Jimmy帮忙照顾。请用下面的提示词给Jimmy写份留言。 take care of, take for a walk, feed and give some water, play with him, clean
Dear Jimmy, _____________________________________________________________________________________________________________________. Li Ming
