Unit 4 Don't eat in class. SectionA 3a-3c(共24张PPT)

(共24张PPT)
Unit4 Don't eat in class.
Section A grammar 3a-3c
Discussion
Tell others about your school rules. (You can finish it by yourself/ with your partner)
In our school, we can’t listen to music in class, but we can listen to it after class.
listen to music
Don't __________
________.
Don't _______.
run in the hallways
fight
祈使句用来表示请求、命令或建议。祈使句的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点，表示较强语气时用感叹号。为表示礼貌，可在祈使句句首或句末加please。 句末用please时，前面通常加逗号，即用“Please…”或“…， please.”句式。若有称呼语，要用逗号隔开，放在句首或句末。
[探究1 祈使句]
1. 祈使句的肯定形式：____________＋其他．
Please buy some bananas for me.
请为我买一些香蕉。
2．否定形式：在动词原形前加don't。
Don't eat here! 不要在这里吃东西！
Don't be noisy! 别吵！
动词原形
3．let 引导的句子也是祈使句的一种。其肯定形式为“Let＋sb.＋____________＋其他．”；否定形式为“Let＋sb.＋________＋____________＋其他．/Don't let＋sb.＋____________＋其他．”
Don't let them play with fire. 别让他们玩火。
4．“No＋n./v. ing！”常用于标识语。
No smoking! 禁止吸烟！ No photos! 禁止拍照！
动词原形
not
动词原形
动词原形
Can we eat in the classroom
No, we can’t, but we can eat in the dining hall.
Can we wear a hat in class
Yes, we can./ No, we can’t.
1. 在本单元中， can 表示许可， 否定时在can的后面加not。
You can't arrive late for school.
你上学不能迟到。
2. Can还表示“能；会;”
She can play the guitar.
她会弹吉他。
[探究2 can的用法]
What are the rules
We must be on time for class.
Does he have to wear a uniform at school
Yes, he does./
No, he doesn’t.
What do you have to do
We have to be quiet in the library.
1．have to 表示客观上“不得不”，侧重指客观上的需要，主语是第三人称单数时，用has to。其否定形式是don't have to或doesn't have to。
I have to finish my homework first.
我必须先完成我的作业。
She doesn't have to get up early.
她不必早起。
[探究3 have to与must]
2．must 表示主观需要或受责任感的驱使认为有必要或有义务去做某事，通常译为“必须”。否定形式mustn't (一定不要，禁止)。
We must be there on time.
我们一定准时到达那里。 (受责任感的驱使)
注意：在含有must 的一般疑问句中，肯定回答为“Yes，主语＋must.”，否定回答为“No，主语＋needn't/don't have to.”
Do you know the meaning of these signs
Don’t run.
Don’t walk.
Walk.
Run.
Write the rules for the school library.
3a
Library Rules
Don’t talk.
__________________
__________________
__________________
Don’t listen to music.
Don’t eat or drink.
Don’t take photos.
Use the words to make questions about the rules. Then write answers according to your school.
3b
1. Be quiet (she/have to /in the library)
Q: Does she have to be quiet in the library
A: Yes, she does.
2. Eat (he/have to/in the dining hall)
Q: _______________________________________
A: _______________________________________
Does he have to eat in the dining hall
Yes, he does.
3. Listen to music (we/can/in the hallways)
Q: _______________________________________
A: _______________________________________
4. Wear a hat (we/can/in the classroom)
Q: _______________________________________
A: _______________________________________
Can we listen to music in the hallways
No, we can’t.
Can we wear a hat in the classroom
No, we can’t.
Make up five cool rules for your dream school. Share your rules with the class. Your classmates vote for the Coolest School!
3c
1. We can eat in class.
2. We don’t have to come to school every day.
3. …
At my dream school, we don’t have to come to school every day. We can eat in the classroom.
We can listen to music in class...
Exercise
(　　)1. [2019·桂林] ________ more books, and you will improve(提高) your reading skills.
A. Reading
B. Read
C. Reads
B
(　　)2.—Mom, can I go skating
—______, but you have to wear a coat. It's cold outside.
A. No, you can't B. Yes, please
C. Yes, you can D. No, you can
C
(　　)3.2017·青岛 We should keep quiet in the cinema. We ________ speak loudly.
A. can B. must
C. needn't D. mustn't
D
GOOD JOB