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(2)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，即主观上的必要。 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.His parents were out. ③ 在否定结构中： don't have to 表示"不必"; mustn't 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。 情态动词的用法要点 一.can和could 情态动词用法例句 can/could 表示能力1.“I don’t think Mike can type.” “Yes, he can.” 2.I can speak fluent English now , but I couldn’t last year. 在肯定句中，表示客观可能性，并不涉及具体某事会发生，常用来说明人或事物的特征。要表达具体某事实际发生的可能性时，不用can，需用could，may，might。1.As a human being, anyone can make a mistake. 2.I’m confident that a solution can be found. 3.He can be very forgetful sometimes. 4.I may stay at home this weekend.(实际可能性) 5.Peter might come to join us.(实际可能性) 6.It will be sunny in the daytime ,but it could rain tonight.(实际可能性) 表示请求和允许。表示请求，口语中常用could代替can，使语气更委婉。1.Can we turn the air conditioner on? 2.Any police officer can insist on seeing a driver’s license. 3.In soccer, you can’t touch the ball with your hands. 4.Could you have her call me back when she gets home, please? 5.I wonder if I could just ask you to sign this. 表示对现在的动作或状态进行主观的猜测，主要用在否定句和疑问句中。1.It can’t be easy caring for a man and a child who are not your own. 2.Can the man over there be our head master? 表示惊异、怀疑、不相信等态度，主要用在否定句、疑问句和感叹句中。1.Can this be an excuse for not giving them help? 2.This can’t be true. 3.How can you be so crazy. 特别说明： (1)could用来表示请求时，语气委婉，主要用于疑问句，不能用于肯定句，答语应用can(即：could不能用于现在时态的简略答语中)。如： ——Could I use your dictionary? ——Yes, you can.(否定回答可用：No, I’m afraid not.) (2)can和be able to辨析 can(could)和be able to都可以表示能力，意思上没有区别。但can只有现在式和过去式，而be able to则有更多的形式。如： I’ve always wanted to able to speak fluent English. Those bags look really heavy, are you sure you’ll be able to carry them on your own? 但是，表示在过去某时的某一场合经过一番努力，终于做成了某事，通常不用could，而用was/were able to来表示。这时，was/were able to相当于managed to do或succeed in doing。如： After the accident it was a long time before she was able to walk again. The fire was very big, but most people were able to escape from the building. (3) 惯用形式“cannot …too…”表示“无论怎么……也不(过分)”。如： You cannot be too careful.你越小心越好。 惯用形式“cannot but+ 不定式(不带to)”表示“不得不，只好”。如： I cannot but admire her determination.我不得不钦佩你的决心。 二.may和 might 情态动词用法例句 may/might表示允许、许可。否定回答一般用must not/mustn’t,表示“禁止、阻止”之意，但也可以用had better not (最好别)或may not(不可以)，语气较为委婉。1.May I come in and wait? 2.——May I smoke here? ——No, you mustn’t(或No, you’d better not.) 在表示请求、允许时，might比may语气更委婉些。用May I征询对方许可在文体上比较正式，在口气上比较客气，在日常用语中，用Can I征询对方意见更为常见。1.Might I borrow your pen? 2.I wonder if I might speak to your son. 表示可能性的推测，通常用在肯定句和否定句中，含有“或许”“大概”“可能”之意;用might代替may时，则语气显得更加不肯定。1.It may rain this afternoon. 2.She might come to join us this afternoon. 3.I suppose he might have missed the train. may用于祈使句表示祝愿1.May you succeed. 2.Long may he live! 愿他能持续住下去。 3.May you have many more days as happy as this one. 4.May she rest in peace.愿她安息。 惯用句式： “may well+ 动词原形”，意为“完全能，很可能”，相当于to be very likely to “may as well或might(just)as well+动词原形”意为“最好，满可以，倒不如”，相当于“had better或there is no reason to do anything else.1.It may well change forever the way you look at Greek art. 2.There may well be a real problem here. 3.There is nothing to do, so I may as well go to bed. 4.You may as well tell us now, we’ll find out sooner or later. 5.I suppose we might as well go home. 6.And if you have to plough the field anyway, you might as well plant it at the same time. 二.must和have to 情态动词用法例句 must表示“必须，应该”之意，语气比should，ought to强烈。其否定形式mustn’t表示“不准，不应该，禁止”等意1.You must come to school on time. 2.Everybody must obey the law. 3.You mustn’t drive so fast in the street. 4.We mustn’t waste any more time. 在回答带有must的问句时，否定回答常用needn’t或don’t have to，表示“不必”，而不用mustn’t1.—Must I come back before ten? —Yes，you must.(No, you needn’t) 表示有把握的推测，意为“一定、准是、相必”，只用于肯定句中1.It must be my mother. 2.You must be hungry after a walk. 3.There must be a hole in the wall. have to have to“必须，不得不”，意义与must相近。但must表示的是说话人的主观看法，而have to则往往强调客观需要。1.The film is not interesting. I really must go now. 2.I have to go now, because my mother is in hospital. must只有一种形式，即现在式与过去式都是一种形式，而have to则涉及各种人称、时态等方面的变化形式。1.I had to work hard when I was your age. 2.I will have to learn how to use a computer. 3.In order to take the exam, we’ll have to finish the whole book by the end of this month . 两者的否定意义不同，mustn’t表示“禁止，不许”，don’t have to表示不必。1.You mustn’t go there. 2.You don’t have to go there. 四.shall和should 情态动词用法例句 shall用于第一、二、三人称构成的疑问句，表示征求对方意见或请求指示1.Shall I open the window? 2.Shall we say 6 o’clock, then? 3.What shall I get for dinner? 用于第二、三人称陈述句中，表示说话人给对方的命令、警告、允诺或威胁。1.Don’t worry, you shall get the answer this afternoon.(允诺) 2.He shall be sorry for it one day, I tell you. (警告) 3.You shall do as I say. (命令) 4.If you children don’t do as I tell you, you shall not go to the party. (威胁) should表示劝告或建议，意为“应该”1.What should I do? 2.Should I trust him? 3.You should read his new book. 表示推测，用在肯定句中，对现在的情况或可能发生 的事的主观推测或期待。意为“想必，大概，或许”1.It should be a nice day tomorrow. 2.Try phoning Robert, he should be home now. 3.He should be around sixty years old. 还可以用在if引导的条件句中，表示一件事听起来可能性很小，但也不是完全不可能，相当于“万一”的意思。从句谓语用should+动词原形构成，主句都一定用虚拟语气1.Ask Tom to ring me up if you should see him. (你万一见到汤姆，请让他给我打个电话) 2.Should I be free tomorrow, I’ll come. (万一我明天有时间，我就过来) 3.If things should change suddenly, please let me know. (万一情况突变，请通知我) 用于疑问句或感叹句中，表示意外、惊异的情绪，意为“竟会”，与why，what，how，who连用，如果是疑问句，则不需要回答。1.Why should anyone want to marry Tony? 2.Don’t ask me. How should I know? 五.will和would 情态动词用法例句 will/would用于表示意志或意愿。will指现在，would指过去。1.He is the man who will go his own way. (他首歌自行其是的人。) 2.They said they would meet us at 10:30 at the station. 表示请求、建议等，用would比用will委婉、客气。1.Will you please take a message for him? 2.Would you please tell me your telephone number? 表示习惯或倾向，意为“总是，惯于”。will至现在，would指过去。1.Fish will die without water. 2.People will talk. (人们总会说闲话。) 3.When we worked in the same office, we would often have coffee together. 表示推测，意为“很可能，大概”。will表示推测比should把握大，比must把握小。1.These things will happen. 2.That will be the messenger ringing. 3.It would be about ten o’clock when he left home. 表示功能，意为“能，行”。惯用形式：will do/would do表示“解决问题”、“就行”。1.That will be all right. 2.Either pen will do. 3.It would not do to work too late.(工作太晚不行。) 用于否定句中，意为“不肯”、“不乐意”1.I won’t listen to your nonsense. 2.No matter what I said, he wouldn’t listen to me. 特别说明：would与used to辨析 would可用来表示过去反复出现的动作，但不能表示过去存在的状态，所以我们不能说：“she would be a quiet girl.” 另外，would强调过去某种特定情况下的活动，是完全过去的事情，同现在没有联系。而used to则着眼于过去和现在的对比，隐含现在已不存在，动作或状态都可表示。Would可以表示不规则的习惯，used to则不可。如： He used to be a naughty boy and cause trouble. I used to get up at six in the morning. Sometimes she would take a walk in the neighboring woods. In those days, whenever I had difficulties, I would go to Mr. Chen for help. (二)情态动词can的用法： 情态动词can 的过去式为could ，(有时could表示更委婉的语气。) ①表示能力、功能等：“ 能，能够，会”： 例句: We can and must overcome our shortcomings. 我们能够而且必须克服我们的缺点。 ②表示可能性： “可能;可以;会”： 例句: In winter the winds can be very cold. 冬天的风会很冷的。 ③表示从内心里可以接受： “可以，能够” 例句: I can regard you as my brother but you must obey what I tell you . 我可以把你看做我的兄弟，但是你必须听我的话。 ④表示请求、要求、建议等： “可以”： 例句: Can you help me to carry these books to the classroom? 你能不能帮我把这些书送到教室去? ⑤表示允许等： “可以”： 例句: You can have my seat.I'm going now. 你可坐在我的座位上，我现在就走。 【注意】can表示能力可和be able to互换使用，且后者有更多的时态，be able to常被用来表示can所不能表示的将来或完成时的概念。 other ,the othe,others,another好像都有“别的”这个意思，你能分清吗? (1)another既可作形容词又可作代词，泛指“再一个，又一个”，表示“总数为三个以上中任意的另一个”，表示泛指，可以单独使用。作定语时，修饰可数名词单数，其前不加冠词。 This dress is dirty,please change another one for me. 这件裙子脏了，再给我换一件吧。 (2)the other表示“两个数量中的另一个”，表示特指，总数为俩;它可以单独使用，也可用the other+可数名词单数。例如; His parents both work in a hospital. One is a doctor and the other is a nurse.他父母都在一家医院工作。一个是医生，一个是护士。(父母为两个人) (3)others用于泛指一些人或事物中其他的，可单独使用或用other+复数可数名词来代替。注意others后面不可直接加名词。例如： ①Some students like English and other students (others) like physics. 有些学生喜欢英语，有些学生喜欢物理。 ②We must think more of others. 我们必须多想想别人。 (同学们：这可是好品质哦!) (4)the others指一定范围内其余所有的人或物，表示特指。也可用the other+名词复数来代替。 This dictionary is better than the others. 这本词典比别[其余]的好。 【补充】else adv.别的. (用于疑问词、不定代词后)其他,另外 I'm going to take you somewhere else. 我要带你去别处。 I don't think there is anything else we need to discuss tonight. 我认为今晚我们不需讨论别的事了。 Is there anything else you want?你还要些别的什么吗? Who else is there in the house?屋子里还有谁? someone else's books (别人的书) (责任编辑：admin) |