解讀haveto與must的用法

1、    解讀“haveto”與“must”的用法    王玉萍have to意為“必須;不得不”強(qiáng)調(diào)外界客觀因素要求主語“不得不做某事”，表示客觀上的需要，有人稱和時(shí)態(tài)的變化，其后接動(dòng)詞原形。have to可用于多種時(shí)態(tài)，形式隨時(shí)態(tài)變化而變化，還可以用在其他情態(tài)動(dòng)詞之后。具體用法如下：1. have to后接動(dòng)詞原形，意為“必須做;不得不做”。如：we have no food home， you have to go and get some， tom. 家里沒有食物了，湯姆你得去買一些來。2. have to 有人稱、數(shù)和時(shí)態(tài)的變化，其第三人稱單數(shù)形

2、式為has to，過去式形式為had to。如：she has to help her mom make dinner. 她不得不幫她媽媽做晚飯。i had to do my homework last night. 我昨晚必須做作業(yè)。3. 含有have to， has to的句子需分別借助動(dòng)詞do， does構(gòu)成疑問句或否定句。如：do they have to go now？ 他們必須現(xiàn)在回家嗎？you don't have to go if you don't want to. 如果你不想去，你就不必去。must意為“應(yīng)該，必須”，mustn't意為“不應(yīng)該，不準(zhǔn)

3、，不允許，禁止”。使用must應(yīng)注意以下幾點(diǎn)：1. must表示主觀義務(wù)，意思是“應(yīng)該，必須，一定”，其否定式mustn't意為“不應(yīng)該，不準(zhǔn)，不允許，禁止”。而不表示“不必”。如：we must get there before five o'clock. 我們必須在五點(diǎn)前趕到那里。you mustn't be late for school. 你千萬不要上學(xué)遲到。對(duì)用must所提問題的否定回答，常用needn't或don't have to，意為“不必”。如：must i stay here after school？ 放學(xué)后我還要留在這里嗎？no，

4、 you needn't / don't have to. 不，沒有必要。must i clean all the rooms？ 我必須打掃所有的房間嗎？no， you needn't / don't have to. 不，你不必。2. must表示推測(cè)，意為“一定，必定”（用于肯定句中）。he must be our headmaster. 他肯定是我們的校長。【鞏固訓(xùn)練】i. 選擇填空。1. at school i _ wear a uniform and i_ keep my hair short.a. can't; have tob. have

5、to; mustc. don't have to; mustd. does; has to2. must i return the book this week？no， you _. you can _ it for 20 days.a. mustn't： keep   b. needn't; borrowc. needn't; keep d. mustn't; borrow3. can you please stay here a little longer？sorry， i _. i _ eat dinner with my mother.

6、 she's coming.a. mustn't; will have tob. don't; have toc. can't; had tod. can't; have to4. _ does jim _ study hard these   days？he will take an exam next week.a. how; have to    b. why; have toc. what; have to   d. when; has to5. mrs green _ go far if she

7、 goes shopping. the supermarket is beside her neighbourhood.a. have to         b. doesn't have toc. needn't have to d. haven't to6. this book _ tom's， because his name    is on the book.a. maybe         b. may bec. must be   

8、0;     d. must7. the girl in the classroom _ be maria. she called me from the library just now.a. mustn't     b. may notc. can't     d. needn't8. we _ use mobile phones when the plane takes off.a. may not       b. couldn'tc. needn't &#

9、160;     d. mustn't9. it's raining， so i _ stay at home.a. have to       b. can'tc. don't have to   d. needn't10. how do you usually go to school？my school is far away. i _ take the bus to school.a. need   b. mightc. have to      

10、 d. mayii. 按要求完成下列句子，每空一詞。1. zhang lin has to clean her room on friday.（改為否定句）zhang lin _ _ _ clean her room on friday2. mary has to help her mother with cooking. （改為一般疑問句）_ mary _ to help her mother with cooking？3. they have to do some cleaning on sunday. （對(duì)畫線部分提問）_ _ they have to _ on sunday？4. ch

11、ildren  must sit in the front seat of a car. （改為否定句）children _ sit in the front seat of a car.5. must i hand in （上交） my homework now， mr. smith？no， you _. （否定回答）iii. 填入方框內(nèi)單詞，使句意完整通順，使用次數(shù)不限。have to  must  can  can't  mustn't1. i _ arrive late for class. i _ be on time.2. i _ keep my hair short and wear a school uniform.3. i _ liste