(共21张PPT)
Unit 6 Electricity
Period 4 Grammar
1
definition and common rules
What is the modal verb
We must keep electrical appliances away from water.
We must hold the plug when we plug in or remove the plug.
We mustn't play near power lines and electrical equipment.
We mustn't swim when it is lightning and raining.
In the last class, we learned some electrical safety tips：
What if I remove the must and mustn’t
The speaker’s mood and attitude changed without modal verbs!
don’t
don’t
She buys electricity in packets.
She must buy electricity in packets.
She can buy electricity in packets.
She may buy electricity in packets.
情态动词表示说话人对动作的情感态度
情态动词不单独出现，需与动词原形连用
情态动词一般没有人称和数的变化
What is the modal verb
1
definition and common rules
In this class, we will learn modal verbs:
must
can
may
Daisy and Benny have to stay at home by themselves. Let’s find out how they spend their day at home.
A day at home
Daisy’s parents are on business
Focus on how they use must, can, may in conversations.
2
the scene
A day at home
Daisy! Wake up! You must have a look at your room. It’s in a mess!
Sorry. I’ll tidy it up. Must I take out all the trash
No, you needn’t. I’ll take it out after breakfast. But you mustn’t mess up the room again.
3
must/mustn’t
Find out the usages-- must
观察must 此时表示什么？
To tell people what to do or what not to do.
肯定句： You must take out all the trash.
否定句： You must not/mustn’t do that.
一般疑问句: Must I take out all the trash
回答： Yes, you must./ No, you needn’t.
句式变化
You must have a look at your room.
You mustn’t mess up the room again.
Must I take out all the trash
No, you needn’t.
必须
主语+must+动原
主语+must not/ mustn’t+动原
Must+主语+动原(must提前)
肯定回答must,否定要用needn’t
3
must/mustn’t
Drills
看图片，用must造句，并进行句式变换。
肯定句:
___________________________when we come back from the outside.
否定句:
___________________________when we come back from the outside.
一般疑问句:
___________________________when we come back from the outside
回答：
___________________________
We must wash our hands
We must not /mustn’t wash our hands
Must we wash our hands
Yes, we must./ No, we needn’t.
3
must/mustn’t
A day at home
Sorry sweeties, can you two cook by yourselves I cannot cook for you. Your father and I won’t be back until this weekend.
Oh, don’t worry Mum. We can take good care of ourselves!
4
can/can’t
A day at home
Benny, can you help me with the lunch It’s difficult to cook!
Yes, I can. Take it easy! I’m coming!
4
can/can’t
Find out the usages-- can
观察can此时表示什么？
To express abilities.
To make a request and give permission.
肯定句：I can cook for you.
否定句：I cannot/ can’t cook for you.
一般疑问句: Can you cook for me
回答： Yes, I can./ No, I cannot/ can’t.
句式变化
We can take good care of ourselves!
I cannot cook for you.
Can you help me with the lunch
Yes, I can.
能力/请求许可
主语+can+动原
主语+cannot/ can’t+动原
Can+主语+动原(Can提前)
肯定can,否定can’t
4
can/can’t
Drills
根据左侧图片，用can或cannot补全对话。
4
can/can’t
Benny: Daisy, __________ you wash your hands correctly like Mum and Dad do
Daisy: Yes, I __________ wash my hands in a right way! Mum taught me before.
Benny: Cool! __________ you teach me how to do it Because I __________ do it well.
Daisy: Yes, you __________ practice with me.
cannot/can’t
can
can
can
Can
A day at home
Sis, it’s 5:00 p.m. now! May I watch the TV for a while
No, you may not. But you may do that after washing the dishes!
5
may/may not
Find out the usages-- may
观察may 此时表示什么？
To make a request and give permission.
肯定句：You may do that.
否定句： You may not do that.
一般疑问句: May I do that
回答： Yes, you may/can.
No, you may not/can’t.
句式变化
May I watch the TV for a while
You may do that after washing the dishes!
No, you may not.
请求许可
主语+may+动原
主语+may not+动原
May+主语+动原(may提前)
可与can, can’t互换
5
may/may not
非正式语境中，may也可用can替代
Drills
5
may/may not
May/Can
May/Can
can
May/Can
Can
Can也可以用于请求许可，但may更礼貌些
疑问句中，may一般放在I前使用
More to learn
must:一定（一般仅用于肯定句，不用于否定句和疑问句，有把握的推测）
e.g. You must be very tired. Let’s take a rest right now!
may：可能（不用于疑问句中，没有把握的推测）
e.g. You may be very tired. How about taking a rest.
can’t: 不可能(一般用于否定句中，有把握的推测）
e.g. You can’t be tired. You took a rest just now!
6
more to learn
must, may, can 表推测
possibilities
1._______ I finish the work now No, you _________.
2.Don’t worry. You ________ return me this book tomorrow.
3.My grandma is ill. You _______ talk so loudly here .
4.I can’t play with you. I ________finish my homework first.
5.I_________ get up early tomorrow. because I have a meeting.
6._________you please open the window
7. Lily ________ be in the classroom. I saw her there just now!
may
can’t
must
must
Can
Must
needn’t
7
practice
Challenge One
Fill the blanks with must, can or may.
must
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.）
Challenge Two
7
practice
Summary to must, can and may
肯定句：
否定句：
疑问句:
回答：
Sentence structures
Definition and common rules
表示说话人对动作的情感态度
不单独出现，需与动原连用
一般没有人称和数的变化
Usages
must: 必须；一定
can：能力/请求许可；can’t不可能
may：请求许可；可能
H
Homework
Let’s learn more about modal verbs！7BU6 Electricity
Period 4 Grammar教学设计
教学目标：
1.学生能够通过观察句子，归纳出情态动词的功能和基本规则。
2.学生能够在语境中理解情态动词must, can, may的主要用法。
3.学生能够通过练习掌握情态动词must, can, may的用法和句式变换。
教学过程：
Step 1. Definition and Common rules
1.复习上节课的安全用电贴士。 We must keep electrical appliances away from water. We must hold the plug when we plug in or remove the plug. We mustn't play near power lines and electrical equipment. We mustn't swim when it is lightning and raining. 对比有无must的区别，引导学生观察情态动词的作用。 2.给出例句，引导学生归纳情态动词的定义和基本规则。
Step 2. Learning must can may in the scenes.
1. 分别在三个情境中观察学习三个情态动词的用法和句式变换。 2. 分别在三个情境中进行练习must, can, may。
Step 3. More to learn: must, may, can 表推测
1. 对比学习must, may, can 表推测的用法。 2. 在坐标轴上比较must, may, can’t所表示可能性的大小。
Step 4. Drills
挑战一：在空白处填入must, may, can。 挑战二：请说出这些标识分别表示什么。
Step 5. Homework
1.扫描二维码，从网盘中获取拓展学习视频，了解更多关于情态动词的知识。 2.完成练习与评价。
