英语情态动词的用法应注意哪些事项,

题目

英语情态动词的用法应注意哪些事项,

答案

r/>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.
六．need和dare
情态动词 用法 例句
need 用于表示“需要,必要”之意.做情态动词时,仅用于否定句和疑问句,只有现在时,过去式要用needn't have,疑问式用need+人称?,否定式用need not(即needn't）, 1．—Need we leave soon?
—Yes, you must.(No, you needn't)
2．You needn't have hurried.
(=It was not necessary for you to hurry,but you did).你当时不必这么匆忙.
做实义动词时,其变化与一般的实义动词相同,后接带to的不定式（need doing = need to be done ）,过去式用needed、did you need?和didn't need,肯定式用needs/needed/need,疑问式用do、does、did提问,否定式要在前面加don't、doesn't、didn't 1. A job like nursing needs patience and understanding.(need+名词,need understanding=need to be understood,需要被理解)
2．He needs to see a doctor.(need to do)
3．Do you still need volunteers to help clean up after the party?(need somebody to do something)
4．They didn't need to start so early.(do not need to do)
dare 用于表示“敢于”之意.做情态动词,没有人称和数的变化,主要用于否定句、疑问句和条件状语从句中 1．—Dare you tell her the truth?
—Yes, I dare. /No, I daren’t.
3． How dare you accuse me of lying!
4． He daren’t admit this.
用作实义动词时,其变化与一般的实义动词相同.在肯定句中,dare后接带to的不定式；否定句中,dare后既可接带to的不定式,也可接不带to的不定式. 1． Only a few journalists dared to cover the story.
2． He doesn’t dare (to) go there alone.
3． Don’t you dare (to) touch it?
七．ought的用法：
情态动词 用法 例句
ought to do 表示“应该”之意 1． You ought to take care of him.
2． —Ought I go now?
—Yes, you ought to. /No, you oughtn’t to.
表示推测.注意与must表示推测是的区别 1． He must be home by now. (断定他已到家)
2． He ought to be home by now. (不十分肯定)
3． This is where the oil must be. (比较直率)
4． This is where the oil ought to be. (比较含蓄)
说明：should与ought to 表示“应该”时的区别
should 表示自己的主观看法,而ought to的语气中,含有“按道理应该……”之意.若要反映客观情况或涉及法律义务和规定,一般用ought to.如：
You should help them with their work.
You are his father. You ought to get him to receive good education.
八．“情态动词+have done”用法
情态动词+have done 用法 例句
must have done 表示主观上对过去已经发生的行为进行推测,意为“想必,准是,一定做了某事” 1． She must have gone through a lot.
2． He must have visited the White House during his stay in the United States.
may/might have done 表示对过去已发生行为的推测,意为“也许/或许已经（没有）……“.一般用于肯定句或否定句中,不用于疑问句.用might则表示语气更加不肯定. 1． You may have learnt the news.
2． He may not have heard his name called.
3． Sorry I’m late. I might have turned off the alarm clock and gone back to sleep again.
can…have done
cannot have done 表示对过去发生的行为的怀疑和不肯定,通常用在否定句和疑问句中.（can换成could时语气委婉） 1． Where can she have gone?
2． Could he have done such a foolish thing?
3． The boy can’t have finished reading the book so soon because it is difficult even to an adult.
could have done 可用于肯定句中,表示“可能已经……”之意,此外,还可以表示过去能做而没做的事,有一种对过去为付诸实施的事情的惋惜. 1． He could have killed himself driving at a dangerous speed.
2． You could have been more considerate.
3． You could have done better, but you were too careless.
might have done 表示“本来可能……,但实际上没有发生的事情”.另外,还可以表示“本来应该或可以做某事”之意,含有轻微的责备语气. 1． You should not swim in that sea. You might have been eaten by a shark.
2． He might have given him more help, thought he was busy.
should/ought to have done 用于肯定句时,表示本该做某事,而实际上未做；用于否定句时,则表示不该做的事反而做了. 1． He should have known that the police would never allow this sort of thing.
2． You shouldn’t have done it so carelessly.
3． You ought to have returned the book earlier.
4． You ought not to have refused his offer.
needn’t have done 表示做了本来不必去做的事.注意：didn’t need to do表示“没必要做而实际上也没有做某事” 1． You needn’t have watered the plants, for it is going to rain.
2． I didn’t need to buy the dictionary. I had a copy at home.
had better have done 用于事后的建议,含轻微责备的口吻,意为“当时最好做了某事”,其否定式had better not have done表示相反的含义. 1． You had better have started earlier.
2． You had better not have scolded her.
would rather have done 表示“当时宁愿做了某事”,其否定式would rather not have done表示相反的含义,两者都表示“后悔”之意. 1．I would rather have taken his advice.
2．I would rather not have told him the truth.