课程内容

Unit 4《Do it yourself》（2）
Grammar - imperative sentence （祈使句）
Do the action
Guessing Game
Turn left!
Turn right!
Walk on the zebra crossing!
Don't smoke!
No smoking!
Don't play football!
Don't park your car!
Don't eat!
Don't pick the flowers!
Go upstairs!
Go downstairs!
Read and observe(观察)
Turn left!                     Don't smoke!
Turn right!                    Don't play football!
Please go upstairs!            Don't park your car!
Go downstairs!                 Please don't eat!
Walk on the zebra crossing!    Don't pick the flowers!
Draw the conclusion（得出结论）
祈使句的结构如下：
肯定：(Please) + do sth.
否定：(Please) + Don't do sth.
Let's do exercise.
1. Jim, _____ me a hand.
   A. gives   B. is giving   C. will give   D. give
2. _____ careful, Jenny! There is a tree in front of you.
   A. Am   B. /   C. Be   D. Was
3. Let's _____ our time.
   A. not waste   B. no wasting   C. not to waste   D. no waste
4. -- _____ higher, and you will see the house.
   -- OK.
   A. If you stand      B. To stand
   C. When you stand    D. Stand
5. Please _____ do it.
   A. he   B. let him   C. let he   D. him
6. _____ let anyone open the door.
   A. Don't   B. Will   C. Not   D. No
7. -- Don't be late again.
   -- Sorry, _____.
   A. I may   B. I must   C. I will   D. I won't
8. -- Call me when you get home.
   A. I must   B. I can   C. I will   D. I may
祈使句的句型：
肯定  Be quiet.  →  1. 动词+…
      Please have a seat.  →  2. Please+动词…
      David, pay attention.  →  3. 人名+动词…
否定  Don't be afraid.             \
      Please do not make a noise. — 在动词前面加don't否定
      Alan, don't be late.         /
Giving orders/instructions
祈使句：是表示请求、命令、建议等句子，通常说话的对象是第二人称you，you常被省略。
祈使句常见题型：
1. Let's + (not)动词原形…
   Eg. Let's go home together. / Let's not talk in the class.
2. let's ..., shall we?   \
3. Let sb ..., will you? — 反义疑问句
4. 祈使句, will you?      /
祈使句
·祈使句，无主语，只用动词就可以。
·表示请求或命令，加上please表客气。
·如果变成否定句，Don't开头是规律。
·No talking!是警示，祈使句用法要牢记。
Complete the dialogues with Imperatives.
1. -- It's her birthday next week.
   -- Then _________ her about the surprise birthday.
2. -- How can I get to People's Hospital?
   -- _________ along the street and _________ left at the lights.
3. -- We have to finish the work in two hours.
   -- Then let's _________ any time.
4. -- _________ so much noise, please.
   -- Ok.
5. -- _________ out! There's a car coming.
   -- Thanks.
Let's do more exercises.
Choose the correct answer.
1. -- Call me when you get home.
   -- OK, _____.
   A. I must   B. I can   C. I win   D. I may
2. Jim, _____ me a hand.
   A. gives   B. is giving   C. give   D. will give
3. Let me _____ on duty today.
   A. am   B. /   C. be   D. do
4. Let's _____ our time.
   A. not waste      B. no wasting
   C. not to waste   D. no waste
5. -- _____ higher, and you will see the house.
   -- OK.
   A. If you stand      B. To stand
   C. When you stand    D. Stand
6. _____ forget to write to me when you _____ get there next Tuesday.
   A. Don't; will    B. Please; will
   C. Please; /      D. Don't; /
7. Please _____ do it.
   A. he   B. he let   C. let him   D. him
8. _____ come in, please.
   A. Will   B. Do   C. Won't   D. Did
9. _____ careful!
   A. Be do   B. Do be   C. Not   D. Not do
10. _____ let anyone open the door.
   A. Don't   B. Will   C. Not   D. No
11. Let John finish the work all by himself, _____?
   A. shall we   B. will you   C. do you   D. do we
12. -- Let's go home, shall we? -- _____.
   A. That's right        B. That's all
   C. That's all right    D. All right
13. Please turn on the light, _____?
   A. are you   B. shall we   C. shall I   D. will you
14. Don't tell him the fact now, _____?
   A. shall we   B. shall you   C. will you   D. do you
15. Let the children not make so much noise, _____?
   A. shall we   B. will you   C. shall I   D. do you
16. _____ 6 and 4, and you will get ten.
   A. Added   B. Adding   C. To add   D. Add
17. _____ late again, or I'll report it to your father.
   A. Don't be   B. You aren't
   C. Can't be   D. Aren't
18. Don't interrupt her when she is speaking, _____?
   A. won't you    B. will you
   C. shall we     D. shan't we
19. _____ get off the lorry until it stops.
   A. Do   B. Can't   C. /   D. Don't
20. Let's not begin our supper until father comes back, _____?
   A. will you    B. won't you
   C. shall we    D. shan't we
生活中的祈使句
in class
1. Be quiet.           
2. Take notes.     
3. Listen to the teacher carefully.
4. Don't eat in class.
   ...
in the restaurant
1. Line up.
2. Don't push.
3. Don't make noise.
4. Don't waste food.
   ...
on the road
1. Walk on the zebra crossing.
2. Be careful.
3. Don't play football.
4. Don't run fast.
   ...
Summary
祈使句结构如下：
肯定：(Please) + do sth.
否定：(Please) + Don't do sth.
DO，可以放在动词前，为加强语气用。
如：Do come in, please!
    Do listen to me, please!
    Do open the door, please!
should and had better
We use should and had better when giving advice and telling people what we think is the best or right thing to do.
1、had better是固定词组，意思是“应该；最好”，后接不带to的不定式，其用法相当于情态动词，动词had没有人称或数的变化。had better常用来提出建议，语气较强，往往含有强迫或命令的口气，故常用于长辈对晚辈、上级对下级或平辈之间。该短语指的是现在或将来的情况，而不是指过去。
had better的简略式为：'d better。如：
(1) You'd better go there by bus.
    你最好是坐公共汽车去那里。
(2) We had better start at once.
    我们最好立刻出发。
2、had better的否定是had better not；疑问式是将had放在主语之前。如：
(1) We'd better not tell him the news.
    我们最好不要告诉他这个消息。
(2) Hadn't we better go to the station to meet him?
    我们去车站去接他们不是更好一点吗？
3、在反意疑问句中，疑问部分一般用“had+主语？”，但有时也可用“Will you?”，表示一种请求或建议。如：
(1) You'd better not go out today, had you?
    今天你最好不要外出，好吗？
(2) I must stay at home this afternoon. You had better come to my house, will you?
    我今天下午必须留在家里，你最好来我家，好吗？
4、对长辈或上级说话时，应避免使用had better。比较礼貌的说法是It may/might be better tor you to do sth.。如：
   It might be better for you to take a taxi.
   你最好是乘出租车去。
ATTENTION
had better后面必须跟动词原形。
这里的had不能用have来替换。如：
You'd better go to hospital at once.
你最好立即去医院看病。
Tom, you'd better go there today.
汤姆，你最好今天去那儿。
主语不论是第几人称，句子不论是什么时态，都要用had better的形式。如：
Now you(he,we) had better listen to the teacher.
你（他，我们）现在最好听老师讲。
We had better be starting back now.
我们最好现在就动身回去。
should的用法
1、情态动词should常用来表示劝告、建议或义务，意思是“应该”，可用于各种人称，其语气比had better委婉，后接不带to的动词不定式。此外，should还可表示合理的推论，意思是“应该；理应；一定…吧”。例如：
(1) You shouldn't come to such a decision hastily.
    你不应该匆忙作出这样的决定。
(2) The party should be great fun.
    那个集会一定很有意思。
2、“should+have+过去分词”常表示如下意思：
（1）表示义务并指过去的情况。意思是“本来应该……（却没有）；要是已经……就好了”，即指过去应该做某事而没有做，含有责备或后悔之意。例如：
   (1) You are right. I should have thought of that.
       你说的对，我应该想到这一点。
   (2) They should not have left so soon.
       他们不应当走得这么早。
（2）表示预期。意思是“应该…了；一定已经…了”，指某个动作到现在应该发生了，只表示一种合理的推测或看法，不含责备的意思。如：
   (1) The train should have already left.
       火车大概已经开走了。
   (2) They should have known the news.
       他们一定知道这个消息了吧。
3、“shouldn't+have+过去分词”表示“本来不应该做，实际上已经做…”
   I was really anxious about you. You shouldn't have left home without a word.
   你本不应该一句话不说就离开家。
should用于一般疑问句时，将should提至句首。
  Should you do like this?
  你应该这么做吗？
陈述句谓语动词含should时候，反意疑问句为：should+主格人称代词或shouldn't+主格人称代词。
  You should study hard, shouldn't you?
  你应该认真学习，是吗？
练习
1. You'd better _____ late next time.
   A. don't   B. not be   C. not being   D. won't be
2. -- Can I leave this door open at night?
   -- You _____ better not.
   A. should   B. would   C. could   D. had
3. -- Let's go to the cinema, shall we?
   -- _____.
   A. Yes, I shall        B. No, I can't
   C. Yes, thank you      D. No, we'd better not
4. -- You'd better go there with me, hadn't you ?
   -- _____.
   A. Yes, I had to       B. Yes, I had better
   C. No, I hadn't        D. No, I hadn't better
5. -- I'm afraid I've got a bad cold.
   -- _____.
   A. Keep away from         B. Never mind
   C. You need medicine      D. Better go and see a doctor
6. We had better wait for your girlfriend Juliet, _____?
   A. hadn't we   B. don't we   C. didn't we   D. shan't we
7. This ddictionary belongs to Rita. You _____ it home without letting her know.
    A. had better not to take   B. shouldn't have taken
    C. oughtn't take            D. shouldn't be taking
8. -- Mary looks sad. Did you tell her about the accident?
   -- Yes, but I _____ her later.
   A. should have told     B. shouldn't have told
   C. must have told       D. ought not to have told
9. -- I didn't see her yesterday.
   -- Oh, but you _____.
   A. should have      B. should
   C. must have        D. cannot have
10. -- I feel rather tired today.
    -- You _____ to sleep too late last night.
   A. should go      B. couldn't have gone
   C. might go       D. shouldn't have gone
Homework
Practice grammar in you exercise book.