sectionA grammar
八下英语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 FocusGrammar 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。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。比如：
--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。 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。1. 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 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.
1._____ 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
Ra.Yes, here you are.
b. Hmm. How much do you need?
c.Yes, sure. No problem. I finished reading
d. it last night.
e.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---b4b 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 foldA: 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
could4c 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 can3. - ____ 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
CanA: 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 takecan; 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。Homework
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
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