情态动词全方位掌握 2022届高考英语语法总复习
情态动词的特征
一、情态动词的功能特征:
情态动词主要用以表明说话者对某一行为的态度和观点。用在行为动词前,表示说话者对这一动作或状态的看法或主观设想。表达说话者的情态主要包括能力、可能、命令、要求、许诺、威胁等。虽然数量不多,但是用途广泛。情态动词是表示语气的单词,本身虽然有一定的词义,但不能独立的作谓语,也没有人称和数的变化,只能和动词一起构成谓语。
二、情态动词的语法特征:
人称和数:情态动词没有人称和数的变化。句法功能:情态动词不能单独作谓语,后跟动词原形共同构成谓语。否定形式:多数情态动词的否定式是在情态动词的后面加not。时态形式:个别情态动词有现在式和过去式两种形式,过去式用来表达更加客气、委婉的语气。句中位置:情态动词在句中放在谓语之前;谓语动词前若有助动词,则在助动词之前。疑问句中则在主语之前。三、常见的情态动词:
can/could, may/might, must/have to, shall/should/ought to, will/would, used to, dare, need, had better, would rather
可以分为四类:
①只做情态动词:may, might, must...
②可做情态动词又可做实义动词:need, dare...
③具有情态动词特征:have to, used to, ought to
④可做情态动词又可做助动词:shall, should, will, would
情态动词can、could和be able to 的用法
(1)表示能力:说话者想告诉别人(某某某)有某种能力。这样的语境中,can,could 和 be able to的用法区别辨析。
can : 表示想做就可以做到的能力,主语原本就具有的某种能力。指现在。eg: I can play the piano. \ You can swim. \ He can understand our words.
could : 泛指过去的能力。could not表示过去没能力或者没成功做某事。指过去。
could是can的过去式。eg: I could not play the piano when I was 6 years old.
Be able to :①表示通过努力可以具备某种能力或实现某种状态,重点强调的是要有一个努力的过程。eg: I am able to play the piano.(隐含着一层我需要努努力就会弹钢琴的意思)I can play the piano.(隐含着一层我本来就会弹钢琴的意思)②过去经过一番努力设法做成某事(也是强调了一个过程,只是这个过程发生在过去,并且成功了或者没成功)意义上相当于:was/were able to = managed to do = succeeded in doing eg: Although the fire spread very quickly, we were able to run away.(虽然大火蔓延很快,我们还是逃脱了)Although the fire spread very quickly, we succeeded in running away.(虽然大火蔓延很快,我们还是成功地逃脱了)Although the fire spread very quickly, we managed to run away.(虽然大火蔓延很快,我们还是设法逃脱了)③can只有原型和could两种形式。而be able to 可用于更多的时态。
eg:One day people will be able to go to the moon on holiday.
I am sorry I haven't been able to answer your letter in time.
情态动词may/might的用法
May aux. 可以,能够;可能,也许;祝,愿;会,能
might
n. 力量;威力;势力
v. 可以;或许(may的过去式);应该
aux. 可能;也许
(1)情态动词 may / might 表可能性
情态动词may和might 表示可能性时,可以对现在、过去、将来,进行推测。might不是may的过去式,它所表示的可能性比may表示的可能性小一些。eg: Tony may/might visit me.
(2)情态动词 may / might 表许可
征求对方许可:may和might没有时间之分,might 比 may 语气更加委婉。eg: Might I come to see you 给予对方许可:可用may,可用can,不能用might。might 一般不表示过去许可,但在间接引语中可做may的过去式,转述已经给予的许可。eg: Mother said that I might play football before supper.法律条文等的客观许可:机关、学校等的文书、公告里的“不得、禁止”在正式的场合下不用can not表示。要用may not 或者 must not。eg: Cars may not be parked in front of the hall.
(3)情态动词 may / might 的习惯用法
May+主语+V原:表示祝愿may/might...but... : 表示承认某事可能是事实,但是......may/might+V原 : 表示有礼貌的劝告,还是......的好以上三种习惯用法的例句:①May she rest in peace.
②She may have lived in the the city for years,but she has never known it.
③You might as well throw your money into the sea as you lend it to him.
Tips :
在so that, in order that 引导的表示目的的句子中常用:may/might,也可用:can/could;其中could和might表示过去的情况。
例句:
We turned on the light so that we might see what it was.
In order that we may get there on time, we should set out early.
情态动词must和have to的用法
Must aux. 必须,一定;可以,应当;很可能
must : 没有时态的变化have to : 有时态的变化(现在时、过去时、将来时、完成时)
情态动词must和have to 的使用方法和区别辨析:
(1)表示义务
must 强调主观上的必须、一定要 / have to 强调客观上的必须、不得不。must 的否定式表示禁止、一定不要 / have to的否定式表示没有义务、没有必要做。not have to=need not(不需要)例句如下:
①Her father said that she must marry, so Tom made a bargain with him.(强调father主观上的必须)
②I have to go home now.(强调客观上有原因导致我现在不得不回家)
③You don't have to tell him the truth.=You don't need to tell him the truth.=You needn't tell him the truth.(强调不需要这样做,但是如果你做了也没所谓)
④All the things mustn't be touched, the ones over there can.(所有东西都禁止触碰,但是那边那些人可以碰)
(2)表示可能性、推测
在肯定句中:表示一件事情有把握的推测,意为一定、肯定。在疑问句和否定句中:用can,不用must。例句如下:①She must be tired after climbing the hill.(说话的人有把握推测她一定很累)②It can't be my sister.She is doing homework at home(3)表示强调
I must admit I dislike that girl.
I must say it gave me quite a shock.
情态动词will/would/used to的用法
will / would - aux. 将,将要,意愿
will
n. 意志;决心;情感;遗嘱;意图;心愿
vt. 决心要;遗赠;用意志力使
vi. 愿意;下决心
aux. 将;愿意;必须
would
aux. 将,将要;愿意
v. will的过去式
(1)情态动词 will/would的使用方法
表示意愿:即自愿或主动提出做什么,如意志、愿望、或决心等,would用于过去的情况。表示请求:用于主语是第二人称的疑问句中,would比will更客气、委婉,不表示过去意义。表示规律性的注定会表示习惯或特性:will用于现在,would用于过去,带有主观性。如下例句
Now and then Tom would stop,look at it and try it against his hand before continuing his task.Oil will float on the water.Would you mind leaving us alone for a few minutes Will you join our discussion
(2)情态动词 used to/would
used to 表示:过去常常。没有人称和数的变化。否定式为usedn't to或者didn't use to.一般疑问句是将used 提到主语前面或用Did...use to...的形式。would只表示过去的习惯动作,与现在无关。如下例句:When he was young,he would smoke a lot.Used they to exercise in high school Where did they use to paly football I didn't use to like opera,but now I am getting interested.
(3)Tips: used to do sth / be used to (doing) sth / be used to do sth 的区别
I used to go to the gym three times a week, but I don't work out any more.I am used to getting up early.This machine is used to cut up waster paper.used to do sth : 表示过去的习惯,译为:过去常常。只能用于表示过去。be used to (doing) sth : 表示:习惯于(做)某事。有时态的变化。be used to do sth : 是use sth to do sth的被动语态形式,译为:被用来做某事。有时态的变化。
情态动词+have+V过去分词的用法
情态动词表示推测共有三种用法:对现在或将来推测、对现在进行情况的推测和对过去的推测。
(1)对现在或将来的推测
情态动词 can/could , may/might , must 等后加动词原形表示对现在或将来的推测。
can/could ①用于否定句或疑问句中,意为:可能。②can和could 没有时态差异,can比could语气强。
may/might ①用于肯定句中(推测判断的语气不确定),意为:也许,可能。
②might 不表示过去,只表示语气比may还弱,意为:或许,大概。
must ①用于肯定句中(推测判断的语气肯定),意为:一定。例句:
I think the old woman must be a nice person.There is no light in the room. She can't be at home now.If you are busy, you may not go.
(2)对现在进行情况的推测
形式:can/could,may/might,must+be+doing。表示:对现在进行的情况的判断和推测。现在进行的肯定的推测:must be doing/may be doing(语气较弱)|现在进行的否定的推测:can't be doing例句:
She may be waiting for you at home.
(3)对过去的推测:情态动词+have+过去分词-表示推测或判断过去的情况
构成:can/could+have+过去分词
用法:①多用于否定句和疑问句中。表示对过去某事发生的可能性的否定或质疑,意为:不可能(已经)......了-(否定句)/可能(已经)......了嘛?-(疑问句)②用于肯定句中。表示对过去没有做某事的遗憾,含有轻微的责备,意为:本来可以......的(但实际上没有......)。语气没有“should/ought to+have+过去分词”强。
构成:should/ought to+have+过去分词
用法:用于肯定句中。表示对过去没有做某事的遗憾,含有责备的意思,意为:本来应该......的(但实际上没有......)。用于否定句中-表示对过去已经做了某事的责备,意为:本来不应该......的(但实际上已经......了)
构成:may/might+have+过去分词
用法:用于肯定句和否定句中,表示对过去发生某事的可能性的推测,意为:或许(已经)....../或许还没有......。
构成:must+have+过去分词
用法:表示对过去发生的事情十分肯定的推测。must表示推测时,不能用在否定句和疑问句中。
构成:needn't+have+过去分词
用法:表示对过去已经做了某事的后悔,意为:本来可以不必......的(可实际上却已经......)
例句分析:
I must have forgotten to tell you.(must 的引入,表达了说话者对过去忘记告诉你的这件事肯定推测)
You needn't have taken a taxi here, for it was very near to my home.
It is too late. He may have gone to bed.
He may not have gone to bed.(肯定句,推测或许还没有上床睡觉)
He should have been asleep.(肯定句,他本应去睡觉的)
He shouldn't have been asleep.(否定句,他本来不应该去睡觉的)
You could have done better,but you were too careless.(肯定句。他能做得更好的)
情态动词后的动词原形形式,一般分为四种:①一般式 ②进行时 ③完成时 ④完成进行时
一般式:情态动词+动词原形
进行时:表示对现在或将来正在进行或将要发生的动作进行推测,意为:或许正在,应当正在,想必正在,准是正在。
完成进行时:改结构表示:应当一直在......|想必一直在......。表示对过去某一时间内一直进行的动作的推测等意义。
完成时:情态动词+完成式表示对过去发生的事情的推测。表示情感和态度,含有责备、批评的意味。常做这种用法的情态动词有:might, could, ought to, should, need等。
后语:在我们说话之前,要想我们需要表达的情感是什么,然后想是肯定句、否定句或者是疑问句。写下一句话后,试着抽离can/could,may/might,should/ought to,must,needn't 等辅助词。多多感悟这些辅助词添加到句子中的意思和说话者的情感。