广东省阳东广雅学校高中英语《Unit2 Healthy eating》教案(5)新人教版必修3

The Fifth Period Grammar
Teaching goals教学目标
1. Ability goals能力目标
Enable students to learn the usages of modal verbs ought, should, needn’t, don’t have to .
2. Learning ability goals学能目标
Help students learn how to choose suitable modal verbs.
Teaching methods教学方法
Practicing (individuals)
Discussion (group work)
Teaching aids教具设备
A recorder, a projector and some slides
Teaching procedures and ways教学过程与方式
Step 1 Lead in
What should/shouldn’t we do to keep healthy?
What kind of food must we eat to be strong?
What ought we to do to stay slim?
Step 2 Modal verbs
What modal verbs have you learned?
can/could may/ might
will/ would had better
shall/ should must
have to need
ought to dare
Step 3 Explanation
1. ought to／should
should 和ought to 都为“应该”的意思，可用于各种人称。

ought to 的语气稍重一些。

You ought to (should) follow your teacher’s advice.
表示主语的义务或责任：
You should take care of your sister．
你应当去照顾你妹妹。

或指出—个正确、明智的动作：
They shouldn't allow parking here；the street is too narrow．
这儿不该允许停车；马路太窄了。

should 和ought to 后面跟动词不定式的完成式,其肯定句表示”过去应该做而未做”, 其否定句则表示”过去不该做但做了”。

You should/ought to have made the decision a week ago.
I shouldn't have made such a foolish mistake.
多数情况下，ought to 可与should互换使用。

ought to的反意疑问句用shouldn’t替代。

2. must和have to
must的用法
1）表示主观的义务和必要, 主要用于肯定句和疑问句, 意思为“必须……，得……，要……”；由must 引起的疑问句，肯定回答要用must或have to, 否定回答要用needn’t或don’t have to, 意思是“不必” ；
must的否定形式mustn’t表示禁止，意思是“不能，不许”。

如：
— Must I finish the task right now?
我现在必须完成这个工作吗？
—Yes, you must. / Yes, you have to.
是的。

(—No, you needn’t. / No, you don’t have to. 不，不必。

)
You mustn’t come here without permission.
未经允许，你不能来这儿。

have to 的用法
1）must表示一种主观的需要，而have to 表示一种客观的需要，意思是“不得不”。

如：
I have to attend an important meeting this afternoon.
今天下午我不得不参加一个重要的会议。

Mother is out, so I have to look after the shop.
妈妈不在家，因此我不得不照看商店。

2）have to 的否定形式是don’t have to, 相当于needn’t。

如：
They don’t have to buy a computer at present.
他们目前没有必要买电脑。

Step 4 Choose the correct answer
1. By lunchtime they would all be sold.
2. His restaurant ought to be full of people.
3. What could have happened?
4. Nothing could have been better?
5. Something terrible must have happened.
6. I will take all that fat off you in two weeks.
7. He could not believe his eyes.
8. He wondered if he should go to the library to find out.
9. He couldn’t have Yong Hui getting away with telling people lies.
10. He had better do some research.
11. After eating in the restaurant people would become fired very quickly.
Step 5 Explanation
The students will learn the usage of modal verbs and try to make the students clear the functions of modal verbs. Then give them some examples.
Step 6 Exercises
Choose suitable modal verbs from below to complete the following dialogues. There may be more than one possibility.
1. SAM: How can I grow thinner, Mum?
MUM: Well, you _______ eat food with plenty of fiber that helps you digest better. And you ______ stop drinking cola or eating sweet food.
SAM: Does it mean I _______ eat my favourite fried chicken any more?
MUM: Not exactly, if you love fried chicken, you _______ give it up. Just eat it less often. You __________________________ worry too much: a little fried chicken ________ do you good!
2. Doctor: You are si ck because you’ve eaten poisonous mushrooms. Where did you get them?
Lucy: I picked then in the forest. I know we _______ eat fresh vegetables. Doctor: Oh, but you ________ eat them until you’re sure they are not poisonous. Lucy: Thank you, doctor. I’ll be more careful next time.
3. CHARLES: I wish I could see things clearly in the dark.
TOM: Eating carrots ________ help you see better. You ________ eat some every day.。