You have worked hard all day .You must be tired.
你辛苦干一整天，一定累了。(对现在情况的推测判断)
He must be working in his office. 他一定在办公室工作呢。
比较： He must be staying there. 他现在肯定呆在那里。
He must stay there。他必须呆
在那。
3) must 表示对已发生的事情的推测时，must 要接完成式。
I didn't hear the phone. I must
have been asleep.
我刚才没有听到电话，我想
必是睡着了。
4) must表示对过去某时正发生的事情的推测，must 后面要接不定式的完成进行式。
---Why didn't you answer my phone call?
---Well, I must have been sleeping, so I didn't hear it。 5) 否定推测用can't。
If Tom didn't leave here until five
o'clock, he can't be home yet. 如果汤姆五点才离开这儿，他此时一定还未到家。
比较have to和must
1) 两词都是'必须'的意思，have to 表示客观的需要， must 表示说话人主观上的看法，既主观上的必要。
My brother was very ill, so I had to call the doctor in the middle of the night.
我弟弟病得很厉害，我只得半夜里把医生请来。(客观上需要做这件事)
He said that they must work hard. 他说他们必须努力工作。(主观上要做这件事)
2) have to有人称、数、时态的变化，而must只有一种形式。但must 可用于间接引语中表示过去的必要或义务。
He had to look after his sister yesterday。
3)在否定结构中：don't have to表示\不必\表示\禁止\， You don't have to tell him about it.你不一定要把此事告诉他。
You mustn't tell him about it. 你一定不要把这件事告诉他。比较may和might
1) 表示允许或请求；表示没有把握的推测；may 放在句首，表示祝愿。
May God bless you! He might be at home。 注意： might 表示推测时，不表示时态。只是可能性比may 小。
2) 成语： may/might as well，后面接不带to 的不定式，意为\不妨\。
If that is the case, we may as well try。
典型例题
Peter ___come with us tonight, but he isn't very sure yet。 A. must B. may C. can D. will
答案B. 表可能性只能用may. 此句意可从后半句推出。
比较can 和be able to
1)can could 表示能力；可能 (过去时用could)，
只用于现在式和过去式(could)。be 副词。so 还可与表示数量的形容词many，few，much， little连用，形成固定搭配。
so + adj. such + a(n) + n。
so + adj. + a(n) + n. such + n. (pl。)
able to可以用于各种时态。
They will be able to tell you the news soon. 他很快就能告诉你消息了。
2)只用be able to
a. 位于助动词后。b. 情态动词后。
c. 表示过去某时刻动作时。 d. 用于句首表示条件。
e. 表示成功地做了某事时，只能用was/were able to， 不能用could。 He was able to flee Europe before the war broke out。
= He managed to flee Europe before the war broke out。 注意：could不表示时态
1)提出委婉的请求，(注意在回答中不可用could)。
--- Could I have the television on? --- Yes, you can. / No, you can't。 2)在否定，疑问句中表示推测或怀疑。
He couldn't be a bad man.
他不大可能是坏人。
比较so和such
其规律由so与such的不同词性决定。such 是形容词，修饰名词或名词词组，so是副词，只能修饰形容词或
so + adj. + n. (pl。) such +n. (pl。)
so + adj. + n. [不可数] such +n. [不可数]
so foolish such a fool
so nice a flower such a nice flower
so many/ few flowers such nice flowers
so much/little money. such rapid progress
so many people such a lot of people
so many 已成固定搭配，a lot of 虽相当于 many，但 a lot of 为名词性的，只能用such搭配。
so?that与such?that之间的转换既为 so与such之间的转换。
动词不定式
动词不定式是初中英语的语法重点之一，也是每年中考英语试题的考点之一。它是动词的一种非谓语形式，没有人称和数的变化，不能单独作句子的谓语。其构成形式为\动词原形\，to为动词不定式的符号，本身无意
义。动词不定式具有两大特点： 1.具有动词的特点，因此，后面可以跟表语、宾语或状语，构成动词不定式
短语。
2.具有名词、形容词或副词的特点，可以在句子中用作主语、宾语、见的句式有：(1)It is +形容词(of sb)to do sth.(2)It is +名词(for sb)to do sth.(3)It takes sb some time to do sth.(4)It is +形容词(for sb)to do sth.句式(1)中常用nice， kind， clever， good， right， wrong， foolish， 宾语补足语、状语、定语、表语及同位语等。下面以近几年全国部分省市的中考英语试题为例，对不定式的难点以及它在中考英语中的考查点，作一简要的总结和分析，供同学们学习时参考。
一、动词不定式作主语
1. It's our duty _________ the room every day.
A. to clean B. cleaned C. clean D. cleans(甘肃省)
2. It's hard for us _________ English well.
A. learn B. learns C. to learn D. learning(江西省)
3.建造这座立交桥将花费工人们一年多的时间。
It will _________ the workers over a year _________ _________ the flyover.(北京市海淀区)
4. It's very nice _________ you to get me two tickets _________ the World Cup.
A. for， of B. of， for C. to，for D. of， to(安徽省)
Keys： 1. A 2. C 3. take， to，build 4. B
[简析]动词不定式作主语时，可以直接放在谓语动词前面的主语位置，也可以用先行词it作形式主语，而将真正的主语(不定式)置于后面。常
careless等形容词，与介词of搭配，这些形容词常表述不定式逻辑主语的属性或性质;句式(4)中常用hard，
difficult， easy， important等形容词，与介词for搭配，表示不定式表示的动作、行为的性质。
二、动词不定式作宾语 1. He wants ______ some vegetables.
A. buy B. buying C. to buy D. buys (山西省)
2. Don't forget ______ your homework with you when you come to school.
A. to bring B. bringing C. to take D. taking (福建省)
3. He found it very difficult ______.
A. sleeping B. sleepsC. slept D. to fall asleep (湖南省)
Keys： 1. C 2. A 3. D [简析]在want， like， agree， hope， wish， learn， begin， start， seem， decide， hate， choose， forget， remember等动词后面，可以接不定式作宾语。如果其后接形容词补足语时，则可以用it作形式宾语，而把作真正宾语的不定式放到后面。
三、动词不定式作宾语补足语
1. Robert often asks us ______ his Chinese, so his Chinese is much better than before.
A. help him B. to help him with C. to help with D. helps him with (江苏省)
2. Mr Li often teaches his Japanese friends ______ Chinese food.
A. cook B. cooks C. to cook D. cooked (甘肃省)
Key： 1. B 2. C
[简析]不定式可以用作宾语补足语。后面可以接不定式作宾语补足语的动词有：ask， teach， expect， tell， allow等。
四、动词不定式作状语 1. She went ______ her teacher.
A. to see B. looks C. saw D. seeing (江西省)
2. Meimei likes English very much. She does her best ______ English well.
A. learn B. learning C. to learn D. learns (四川省)
Key： 1. A 2. C
[简析]go， come， try， do / try one's best等动词或短语动词作谓语时，其后常常可以接不定式作目的状语。
3. I'm sorry ______ that. A. hears B. hearing C. hear D. to hear (河北省)
4. I'm sorry ______ you. A. trouble B. to trouble C. troubling D. troubled (吉林省)
5. My mother was very glad ______ her old friend.
A. to meet B. meet C. met D. meets (甘肃省)
Keys： 3. D 4. B 5. A
[简析]\形容词+ to do sth\结构中的不定式作状语，常表示原因或方式。
6. The panda is so fat that it can't go through the hole.(改为意思相同的句子)
The hole ______ ______ ______ ______ such a fat panda to go through. (广东省)
7. The ice on the lake was so thin that people couldn't skate on it. (改为意思相同的句子)
The ice on the lake wasn't ______ enough ______ people ______ ______ ______. (广东省)
Keys： 6. is， too， small，for 7. thick， for， to， skate， on
[简析]在上述\形容词/副词(for sb)to do?\太??而不
能??)和\?\足以、足够??做??)结构中，不定式作结果状语。
五、动词不定式作定语 1. Would you like something ______?
A. drink B. drinking C. to drink D. drinks (湖北省)
2. I have a lot of homework ______.
A. do B. doing C. did D. to do (河南省)
3. He is not an easy man ______.
A. get on B. to get on C. get on 动语态)。2.在\后面接不带to的不定式。
七、动词不定式的否定形式 with D. to get on with (山东省)
Key： 1. C 2. D 3. D
[简析]不定式作定语时，常放在被修饰的词语之后，与被修饰的词语为逻辑上的主谓关系或动宾关系;如果不定式的动词是不及物动词，其后要加上必要的介词或副词，构成的短语动词相当于及物动词。
六、不带to的动词不定式 1. We saw him ______ the building and go upstairs.
A. to enter B. enter C. entering D. entered (河南省)
2. So much work usually makes them ______ very tired.
A. to feel B. feels C. feeling D. feel (吉林省)
3. Your father is sleeping. You'd better ______.
A. not wake up him B. not to wake up him
C. not wake him up D. not to wake him up (陕西省)
4. I was made ______ my homework in the afternoon.
A. do B. doing C. to do D. did (贵州省)
Key： 1. B 2. D 3. C 4. C [简析]1.在see， watch， hear， feel等感官动词和make， have， let等使役动词后面作宾语补足语的不定式不带to.但是在被动语态中，作主语补足语的不定式要带to(let没有被
1. Mr Black asked the man ________ the queue.
A. not to jump B. to not jump C. didn't jump D. not jump (广西壮族自治区)
2. The old man told the child ______ noisy.
A. not be B. not to be C. to not be D. be not (湖北省)
3. There is going to ______ an important meeting tomorrow. Please try ______ late.
A. have， not to be B. have，not be
C. be， not to be D. be， not be (内蒙古自治区)
Key： 1. A 2. B 3. C
[简析]动词不定式的否定形式通常是在不定式符号to的前面加上not，如果是不带to的不定式就直接在动词原形前面加上not.
八、某些动词后面接不定式和接动词-ing形式的区别
1. Please stop ______ a rest if you feel tired.
A. to have B. having C. have D. has (广西壮族自治区)
2. ——Why didn't you buy some bread on your way home? ——Sorry, I forgot ______ some money with me.
A. take B. taking C. to take D. took (湖北省)