语法：情态动词must和haveto.练习

1、语法：情态动词 must、have to和have got to情态动词must和have to都有“必须”的含义，它们的用法如下：（一）、must “必须”、“应该”的用法:1.must表示“必须”、“应该”。 例如： We must protect our environment.（我们必须保护环境。）Everyone must obey the rule.（人人必须遵守制度。）2. must的否定形式must not表示“不应该”、“禁止”、“不准”。语气比较强 烈。例如： You must nr t speak like that你不应该像那样讲话。） You mustn Must与h

2、ave to的区别:must表示的是说话人的主观看法，而 have to则表示的是客观需要。Must 一般只有现在时'而have to有更多的形式。 t be late for school （.你不应该上学迟到。）3. 在回答must的问句时，肯定形式用must来回答，但否定形式用needn 或don1 t have t来回答。而不用mustn1来回答。例如：Must I be home before 8 o ' clock?（之前我必须回家吗？）Yes, you must.No, you needn ' t./No, you don ' t have to.

3、（是，你必须。）（不，你不必。）4. must还可表示推测，意思是“一定”、“必定”，一般只用于肯定句中。分三种 情况：1）对于现在状态的推测，我们用：must +v.（状态动词或系动词），例如： He must be at home.（他准在家里。） There must be some children in the room.（房间里准有些孩子。）2. ）对于现在动作的推测，我们用：must +be + doing （行为动词），例如： They must be cleaning their room.（他们准是在打扫房间。） He must be watching TV .（他准是在看

4、电视。）3. ）对于过去事实的推测，我们用： must +have +过去分词，例如：（I；1 It must have rained last night.（昨晚准是下雨了。） I didn * t hear the phonemust have been asleep.（我没有听至 U 电话，我准是 睡 着了。）（二八have to表示 必须”不得不”例如： He has to stay in bed for 3 or 4 days.（他必须卧床休息三四天。） We will have to get up early tomorrow.（明天我们必须早起。）（三）、have got to是

5、have to的口语形式。例如： I ' ve got to leave for Nanjing 我不得不去南京。） I must go now.（主观看法） My mother is ill, so I have to go now.（客观需要）* Have to 与 have got to 的区 别：have got to虽然是have to的口语形式，但二者在用法上有严格的区别：have to 的前面还可以用情态动词或助动词'而have got to却不可以；haveto 的否定形式为 don1 t/doesn 1 t/didn ' t+ 疑问 e 式为 Do/D

6、oes/Did + 主 语 + have to？而have got to的否定形式是在have后加not,疑问式把have提前。例如： We don ' t have to go home.Do you have to go home?一/ .Fill in the blanks using have to, have got to, must, should, ought to, hadJ We have n t got to go home. Have you got to go home?better.1. Younot get down until the bus has st

7、opped2. Theybe encouraged to speak English after class3. You oftenwait a long time for a bus4. Wego and see Mary tomorrow, but I don t think we will.5 not miss my train.6. When traveling, you take care of yourhealth.7 n some parts of the world, youboil the water beforedrinking it.8 f you have a stom

8、ach pain, youdrink hot weak tea9. Younot swim immediately after a heave meal.10. Younot wake me up when you come in.11. Hebe ill, for he looks so pale.12. Younot have given him the money.13.IVs getting late. I am afraid Igo.二、Choose the best answer.1. Must I do it now?No, you A. needn't B. don h

9、ave to C. mustn't D. A or B2 t's nearly seven o'clock Jackbe here at anytime A. must B. need C should D can.3. When can I come for these photos? I need them tomorrow afternoon.Theybe ready by 12:00. A. can B. should C. might D. need 4.Sorry, I'm late. Ihave turned off the alarm o 

10、9;clock and goneback to sleep again. A. might B. should C. can D. will5told Sally how to get there, but perhaps Ifor her.A. had to write it out B must have written it outC. should have written it out D. ought to write it out6. Jenny have kept her word I wonder why she changed her mindA. must B. shou

11、ld C. need D. would7. Tom ought not to me your secret, but he meant noharm A. have told B. tell C. be telling D. having told8.Sir, you be sitting in the waiting room It is for women andchildren only. A. oughtn ' tto B. can t be C. won ' t D. needn' 19.lf you really want yourself to be in

12、 good health, you mustalways so much A. not, be smoking B not, have smokedC. not, to smoke D be not, smoking10didn 't hear the phone, I asleepA. must be B must have been C. should be D should have been11 was really anxious about you. You home without a wordA. mustn t leave B. shouldn't have

13、leftC. couldn t have leftD. need n't leave12.You'd better go at once,you?A. shouldn' t B. wouldn ' t C hadn ' t D couldn ' 113.She ought to be praised,9A. ought she B. she ought C. oughtn tshe D. she oughtn 114.He go there by train.A. oughtn t to B. oughtn' t C. ought to not D. didn ' t ought to15.Look, it be Mr. Wang.No, it be him. He has gone abroadA. may; mustn t B. must; may not C must; can t D can; may not 三、 Correct the mistake in each sente nee:1.