情态动词表推测用法总结及练习.doc

情态动词表推测用法总结
（一）情态动词表推测的三种句式
能用于表推测的情态动词：must, can, could, will, would, may, might, should, ought to
1.在肯定句中一般用must (一定)，may（可能），might / could（也许，或许）。
　 （1）He must/may/might know the answer to this question?　　他一定/可能/也许知道这个问题的答案。
　　（2）It is cold in the room. They must have turned off the heating.　　屋里很冷，他们肯定把暖气关了。
　　2.否定句中用can’t / couldn’t(不可能), may not/might not(可能不)。
　 （1）It can’t/couldn’t be the headmaster. He has gone to America.　　这不可能是校长，他去美国了。
　　（2）He may not/might not know the scientist.　　他也许不认识那位科学家。　　
3.疑问句中用can/could (能……?)。
　　（1）Could he have finished the task?　　 他可能把任务完成了吗？
　　（2）Can he be at home now?　　 他现在能在家吗？
　　注：以上三种句式中情态动词的语气按程度都是依次递减的。might, could并非may, can的过去式，而表示语气较为委婉或可能性较小。 Couldn’t 比can’t 语气弱一些。　　
　　（二）情态动词表推测的三种时态
　　1.对将来情况的推测，用“情态动词 + 动词原形”。
　　（1）She must / may / might / could arrive before 5.　　5:00前她一定/可能/也许到。
　　（2）She must/may/might/could walk miles and miles among the hills without meeting anyone.
　 　她一定/可能/也许会在山里一连走好几英里而遇不到一个人。
　　2.对目前或一般情况的推测，用“情态动词 + be”或“情态动词 + 动词原形”。
　　（1）He can’t ( couldn’t ) / may ( might ) not be at home at this time.　　这个时候他不可能/可能不在家。
　3.对正在发生动作的推测，“情态动词 +be doing”
（1）He must / may / might / could be listening to the radio now. 他一定/可能/也许正在听收音机。
　　4.对过去情况的推测，用“情态动词 + have +过去分词”。
　　（1）It must / may / might / could have rained last night .The ground is wet.　　地湿了，昨晚肯定/可能/也许下雨了。 （2）The door was locked. He can ( could ) not / may ( might ) not have been at home .　门锁着，他不可能/可能不在家。
　　（3）Can / Could he have gotten the book？　　难道他找到书了吗？　　
补充强调：推测的句型特点（对某一次的推测句型有两部分：语气和时态）
（1）语气部分：（以下情态动词语气由强至弱）
肯定句：must、may、might（=could）
否定句：can’t（=couldn’t）、mayn’t、mightn’t  
疑问句：can、could（语气更加委婉不确定）
（2）时态部分： be表示对现在的推测 have done表示对过去的推测 be doing表示对正在进行的推测
语气部分写在前时态部分写在后，组合在一起就是推测
（三）几组表推测的情态动词用法
“情态动词＋完成时”是历年高考的热点，在做此类练习时，既需要掌握这一结构的基本用法，又应该仔细体会题干所提供的语言信息，准确理解语言环境和说话人的含义，尤其要注意题干中时态给予的暗示。
.must have done 表示对已经发生的事情的推测，意为“一定，想必”, 句子中表示的是一种肯定的推测。这种结构一般只用于肯定句，其否定形式是can’t （couldn’t）have done ，表示“不可能，肯定不会”。例如：
He didn’t hear the phone . He must have been asleep. 他没有听到电话响，他肯定是已经睡着了。
一、单项选择
1 John___ come to see us tonight, but he isn't very sure yet. A. may B. need C. can’t D. must
2 John isn’t in the classroom. He ___ play soccer on the playground with Bob. A. can B. must C. should D. can’t
3 -Will you go to the cinema with us? -No, I ___ rather read a magazine at home.
A. should B. might C. would D. had better
4 You___ go and see a doctor at once because you got a fever. A. can B. must C. dare D. would
5 -Can you speak Japanese? -No, I____. A. mustn't B. can't C. needn't D. may not
6 -He___ be in the classroom, I think. -No, he ___ be in the classroom. I saw him go home a minute ago.
can; may not B. must; may not C. may; can't D. may; mustn't
7 -Is Lena swimming in the pool? -No, she ___ swim. She is terrified of water. A. may not B. must not C. can't D. needn't
8 He isn't at school. I think he ___ be ill. A. can B. shall C. must D. might
9 -What do you think “upset” means? - I’m not sure. It ___ mean “sad”. may B. must C. can D. should
10 The children___ play football on the road. A. can't B. can C. mustn't D. must
二、根据句子意思用must, might, could或can’t填空
1. The white ruler______________ belong to Lucy. Hers is red.
2. I can’t find my keys. They ______________ be still at home.
3. The exercise book______________belong to Bob. It has his name on it.
4. Jim______________ be at home. He has gone to his hometown.
5. This blue shirt ______________ belong to Ken. He likes blue best.
6. The schoolbag ______________ be Paul’s. There are a lot of books in it.
7. The volleyball______________ belong to Alice. She plays volleyball every day.
8. The classroom is clean. Someone ______________ clean it just now.
9. –Is that Bob there? –No, it ______________ be him. He has gone to Shanghai with his family
10. –where is Mr. Lee? –The light in his bedroom is still on. He __________ be there.
11. I ______________ find my pencil case. I think I have lost it.
12. The boy is clever. He ______________ tell many stories when he was young.
13. The man is running fast. He______________ be catching the bus.
14. Li Lei has learned English for 15 years. He ______________ know the meaning of this sentence.
15. –What are you going to do this weekend ? –I’m not sure. I ______________ visit my grandparents.
16. –Who is that boy in blue?
–It______________ be Tim. He is always reading English there every morning.
–It______________ be him. He is talking with Miss Liu in the classroom.
17. I thought you __________ be hungry, so I have brought you some cakes.
18. -Here are some earrings. The owner ______ be a boy.
-Well, it _______ be a boy. The earrings ______ be a present for his mother.
19.-Are you coming to Jeff’s party? -I’m not sure. I ___________ go to the concert instead
20. I have tried to call him at the office, but there is no reply. He______________ be at home.
三、根据所给汉语提示完成句子。
1. 他脸色苍白,准是病了。He looks so pale, he____________________________
2. 她戴着钻石项链，一定很有钱。She’s wearing a diamond necklace. She ____________________________
3. 他现在可能正在打篮球。He _____________________________ basketball now.
4. 我确信她不在家。I’m sure that she ______________ stay at home.
5. 他肯定在花园里散步。He______________ in the garden.
6. 这本字典肯定是我的，上面有我的名字。The dictionary ____________ mine. It has my name on it.
7. 这张CD可能是属于Tony的，因为他喜欢听流行音乐。
The CD ______________ belong to Tony because he likes listening to pop music.
8. 这个发带不可能是鲍勃的，终究他是个男孩。The hair band ______________ be Bob’s. After all, he is a boy!
9．气温可降至—60℃，也就是零下60℃。The temperature ______________ fall to –60℃, that is 60℃ below freezing.  
10．她可能不知道这件事。________________________ ____
11．他担心他们可能不同意他的意见。He was afraid ______________
12．你辛苦干一整天，一定累了You have worked hard all day. ______________
‎13. 再等十分钟，我弟弟可能正开车到这里来。 Wait another 10 minutes! My brother______________ here now.
14.公园里现在肯定有一些老人正在散步。 There _________ some old people taking a walk in the park now.
15. 别玩小刀，你可能会伤到自己的。 Don’t play with the knife. You ______________
when，while，as引导时间状语从句的区别
When 1.表示“当……时候”，“当……之后”之意
(1) 从句中的动词无论是延续性动词，还是短暂性动词都可以用when引导从句，主从句的动作可以前后，或同时发生。使用as , while ,是主从句的动作必须同时发生，并且从句必须是延续性动词，
②Sorry，I was out when you called me．（call为短暂性动词）对不起，你打电话时我刚好外出了。
③Strike while the iron is hot．（is为延续性动词，表示一种持续的状态）趁热打铁。
④ The students took notes as they listened．（listen为延续性动词）学生们边听课边做笔记。(2) 从句中的动词是延续性动词，可以用while或as替代when。
My father is cooking while /when/ as my mother is reading newspapers.
•2. 对两个同时进行的动作或状态进行对比时，多用while，亦可用as/when。
While she was making a phone call, I was writing aletter.
•3. 当主句、从句动作同时进行，从句动作的时间概念淡化，而主要表示主句动作发生的背景或条件时，只能用 as。这时， “一边……，一边……”之意。
The little girls sang as they went. The students took notes as they listened to the teacher.
4.表示“随着……”指时间的推移时，只能用as。
As time went by, the days became colder and colder.
As Christmas are coming nearer, the children got excited.
As  my grandfather is getting old, his memory is getting poorer.
总结： 表示当……时候，当……之后之意，多用when；
表示主从句正在进行的动作或状态的对比时多用while；
while 还可以用作对比”而”，如：My mother likes doing sports; while my father likes watching them
表示一边……一边……；只能用as；表示随着……含义时，只能用as。
Because, since, as, for 表原因的区别
because, as, for, since这几个词都是表示“原因”的连词，语气由强至弱依次为：because→since→as→for;其中because, since, as均为从属连词，引导原因状语从句；而for 是并列连词，引导并列句。
　　1. because表示直接原因，它所指的原因通常是听话人所不知道的，其语气最强。常用来回答why的提问，一般放于主句之后，也可以单独存在。例如：
　　(1)I stayed at home because it rained. 因为下雨我呆在家里。
　　(2)Because Lingling was ill, she didn't come to school. 玲玲因病，没有上学。
　　(3)—Why is she absent? 她为什么缺席？　　—Because she is sick. 因为她病了。
　　此外，在强调句型中，只能用because。例如： (4)It was because I missed the early bus that I was late for school. 我上学迟到是因为我没有赶上早班汽车。
　　2. since侧重主句，从句表示显然的或已为人所知的理由，常译为“因为”、“既然”，语气比because稍弱，通常置于句首，表示一种含有勉强语气的原因。例如：
　　 (1)Since he asks you, you'll tell him why. 他既然问你，那就告诉他为什么吧。
(2)Since everyone is here, let's start. 既然大家都到齐了，我们就出发吧！
(3)Since I understood very little Japanese, I couldn't follow the conversation. 我日语懂得不多，因而听不懂对话。
　　3. as是常用词，它表示的“原因”是双方已知的事实或显而易见的原因，或者理由不是很重要，含义与since相同，但语气更弱，没有since正式，常译为“由于，鉴于”。从句说明原因，主句说明结果，主从并重。例如：
　　(1)We all like her as she is kind. 我们都喜欢她，因为她善良。
　　(2)As I had a cold, I was absent from school. 因为我感冒了，所以没去上课。
　　(3)As Xiaowang was not ready, we went without him. 由于小王没有准备好，我们只好不带他去了。
　　4. for用作连词时，与because相似，但它所表示的原因往往提供上文未交待过的情况。for不表示直接原因，表明附加或推断的理由，因此for被看作等立连词，它所引导的分句只能放在句子后部(或单独成为一个句子)，并且前后两个分句间的逻辑关系不一定是因果关系，其间用逗号隔开，且for不可置于句首，for的这一用法常用在书面语中，较正式。例如：
　　(1)The days are short, for it is now December. 白天短了，因为现在已是十二月份。
　　(2)It must have rained, for the ground is wet. (从“地面潮湿”作出“下过雨”的推测，但地湿并不一定是下雨所致, for不可以换为because。)
　　(3)The ground is wet because it has rained. (“下雨”是“地上潮湿”的直接原因。)
前后两个分句间有一定的因果关系时(有时很难区分是直接原因，还是推测性原因)，for与because可以互换使用。例如： (4)I could not go, for / because I was ill. 我没能去，是因为我病了。
(5)He felt no fear, for / because he was a brave boy. 他没有害怕，因为他是个勇敢的男孩。
or 和 and 用法区别
1. 并列结构中，or通常用于否定句，and用于肯定句。但有时and 也可用于否定句。请注意其不同特点：
There is no air or water in the moon. There is no air and no water on the moon.
在否定中并列结构用or 连接，但含有两个否定词的句子实际被看作是肯定结构，因此要用and。
2. or用于连接并列的单词、词组、短语或句子,表示"或者"的意思。如: 
We can visit the World Park or travel around the world.  我们可以参观世界公园,或者周游全世界。 
3.or用在选择疑问句中,灵活译为"还是"。如:
Is that an apple or an orange?那是苹果还是桔子?
4. or用于否定句中,代替and ,表示"和"的意思。如:  I don't like bread , rice or porridge.我不喜欢面包、米饭和粥。
5. or用于连接两个并列的句子,表示"否则,要不然"的意思。如: Hurry up, or you'll be late.快点,否则你要迟到啦。
but，however， though 区别
but 是连词，连接两个并列句，中间用逗号隔开，表示转折 如： I wanted to buy a book, but I don't have enough money.
though 是副词，但在句中的成分相当于连词。引导从句，不能与but 连用，可以放句首或者句中。意思是尽管如：Though it is so hot I have to go outside. I have to go outside though it is so hot.
however 也是副词，剧中成分相当于连词。可以放在句首或句中，后面一定要用逗号。表转折。放句首时，与前面的句子是转折的连接。放句首时，前后用逗号隔开,如：I wanted to buy a book, however, I do not have enough money

1,It’s going to rain. You’d better take an umbrella ____ you may get wet. A. or B. and C. but
2,Diana isn’t here, _____ leave a message on her desk. A. or B. so C. and D. but
3,He didn’t go to school yesterday _____ he was ill. A. because B. because of C. if D. so
4,I’d like to go with you, ______ I’m too busy. A. or B. and C. so D. but
5,Rick has learned a lot about Chinese culture _____ he came to China .A. before B. when C. until D. since
6,It was raining heavily, ___ we decided to stay at home and watch TV. A. but B. or C. because D. so
7,—I really enjoy Chinese food! —Me, too. My mouth was watering ______ I watched the TV program A Bite of China.
A. when B. before C. since D. after
8,Read this article, ___ you will understand that not everything can be bought with money. A. or B. and C. but 9,He’s not a perfect child. He sometimes talks back _______ his parents talk with him. A. if B. before C. when D. until
练习：在下列各句的空格中填入适当的连词
 1．_________ he comes tomorrow, I shall ask when he was born. 
 2． _________ he was speaking, everybody listened carefully. 
3． It was already eight o'clock _________ we got there. 
4． Have a good look at that man _________ you pass him. 
 5． I waited ________ he came back. 
6.  I was about to go out _________ a visitor came. 
7． The thieves ran away _________ they saw the police. 
8. He learned to speak German _________ he was in Berlin. 
9. She likes everything to be ready ________ she starts to work. 
 10. We played outside till sunset, _________ it began to rain.

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