Unit 4
Don't eat in class.
语法精讲
基础自测
阅读提升
第
2
课时
Section A (Grammar Focus—3c)
一、祈使句
1
．含义：祈使句是用来表示请求、命令或建议等的一种句型。其主语一般为第二人称
you
，但通常省略。祈使句的句末一般用句号，表示较强语气时用感叹号。为了使祈使句显得更委婉、有礼貌，可在开头或结尾加上
please
。
2
．祈使句的五种类型
Do型祈使句
实义动词原形＋其他
Listen to me，please.
请听我说。
Be型祈使句
be 动词＋其他
Be quiet，please.
请安静。
Let型祈使句
Let＋sb.＋动词原形＋其他
Let's play football.
让我们踢足球吧。
Please型
祈使句
Please＋动词原形＋其他
Please stand up.
请起立。
Please don't stand up.
请不要起立。
No型祈使句
No＋
v
．－ing/名词！(表示禁止)
No smoking!
禁止吸烟！
No photos!
禁止拍照！
3
.祈使句的否定形式
通常是在谓语动词前加don't。但要注意以let开头的祈使句，其否定形式是 “Don't＋let＋宾语＋动词原形＋其他．”或“Let＋宾语＋not＋动词原形＋其他”。
4．对祈使句的基本回答：
( 1 )A：Tom, take the box to Mr.Wu's office.
B：肯定回答——Yes, I will.
否定回答——Sorry, I can't carry it.
( 2 )A：Don't listen to music in class.
B：No, I won't.(用于自己之前没做过，同时也表明自己今后也不会做时)或Sorry, I won't do it in future.(用于自
己犯错，被别人禁止时)
( 3 )A：Let's go out for a walk.(“Let's do sth.”常用于提出建议)
B：肯定回答——That's a good idea.或That sounds good.(直接表示赞同)
否定回答——Oh, no.It's too hot.或Oh, no.Let's watch TV at home.(可用“No”作否定回答，并适当解释或提出自己的见解)祈使句一般要对方去做的动作是在将来发生。肯定回答时常用“Yes, I will”；否定回答时常用“No, I won't”等。will为“将要”之意，won't为will和not的缩写形式，为“将不；将不会”之意。
二、情态动词can与have to
1．can能；会
( 1 )表示做某事的能力，其否定式为can't。如：
Can you speak English?
你会讲英语吗？
( 2 ) 表示“允许；许可”。如：
You can keep the book for a week.
这本书你可以借一周。
2．have to必须；不得不
其后接动词原形。have to有第三人称单数形式，即has to，变疑问句和否定句时要借用助动词do/does。如：
We have to go home after school.
我们放学后必须回家。
Ⅰ.用括号内所给单词的适当形式填空。
1．__
__________
__(not play) with fire(火)．
2．Don't
__
______
(run) in the classroom.
3．Let himnot__
_________
__
(not play) the computer games.
4．Can we
__
______
(eat) here?
5．Do you have to _
__
___
_(go) to bed before ten at night?
Don't play
run
not play
eat
go
Ⅱ.根据汉语意思完成句子，每空一词。
1．到这儿来。
______ ________．
2．别在走廊里跑。
_______ _____ in the hallways.
3．快点！
_____ _______！
4．不要在这儿吃东西。
_______ ______ here.
5．让我们骑自行车到那儿吧。
______ _____ the bike to get there.
Come
Don't
Be
Don't
Let's
here
run
quick
eat
ride
Ⅲ.按要求完成下列句子，每空一词。
1．Lily can play the guitar.(改为一般疑问句并作否定回答)
—________ Lily _
______
the guitar?
—No , she _
_______
．
2．Jack has to play the piano every weekend.(改为一般疑问句)
_
_______
__ Jack
______
_
____
_ play the piano every weekend?
3．Be quick.(改为否定句)
_______
_
_____
quick.
4．You can't eat food in class.(改为祈使句)
__
_____
_
_____
food in class.
5．You can't be late for class next time.(改为祈使句)
__
____
_
______
late for class next time.
Can
Play
can't
Does
have
Don't
Don't
Don't
to
be
eat
be
Ⅳ.单项选择。
( ) 1. ________ listen to music in the classroom.
A．Not
B．No
C．Don't
D．Doesn't
( ) 2. Tom，please ________ the classroom now.
A．clean
B．to clean
C．cleans
D．cleaning
( )
3. Let's ________ on time for classes.
A．be
B．be not
C．are
D．is
C
A
A
B
( ) 4. She has to ________ her homework every night.
A．does B．do
C．doing D．did
( ) 5. Sorry，you ________ play basketball in the classroom.
A．can't B．don't
C．don't have to D．doesn't
A
Dear Sam
，
Here are some __
1
__ for you when your dad and I are not at home.__
2
__
，
get home early.Don't play __
3
__ after school.Second
，
take care of(
照顾
) your brother and don't __
4
__ with him.Third, help your grandma do the __
5
__ after dinner.
fight
dirty
dish
rule
before
follow
outside
keep
one
practice
Ⅴ
.
选词填空。
阅读短文，从方框中选择适当的词并用其正确形式填空，使短文通顺、意思
完整。每词限用一次。
Fourth
，
remember to __
6
__ the piano for one hour every evening.Fifth
，
go to bed __
7
__ 10 o'clock.The last one, __
8
__ your room clean and don't leave your __
9
__ clothes everywhere.Your dad and I will be very happy if you can __
10
__ the rules.
1
．
______
2
．
______
3
．
_________
4
．
______
5
．
_______
6
．
_________
7
．
_______
8
．
______
9
．
_______
10．_______
rules
First
outside
fight
dishes
practice
before
keep
dirty
follow
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