（一）情态动词常考点
（一）表能力
如：I am starving to death;I can eat two bowls of rice now;
现在的能力我快饿死了,现在我能吃两碗米饭;
If you have a good sleep,you will be able to work out this problem;
将来的能力如果你好好睡一觉,你将能够解出这道题;
The fire spread through the hotel very quickly but everyone was able to get out;
过去有能力做并且成功的做了某事尽管这场大火迅速蔓延到了整个宾馆,但是每个人都能够逃出去;
I could have worked out the problem,but I didn’t;
过去有能力做但未做我本来可以解决这个问题,但没有解决;
踊跃的近义词
（二）表推测可能性
1.可能性可分为客观的可能性和具体事情实际发生的可能性两种;所谓客观的理论的可能性即并不涉及具体某事是否会发生,此种用法常常可以说明人或事物的特征;情态动词can可用于肯定句中表示客观的理论的可能性,而表示具体事情实际发生的可能性时,can一般不用于肯定句;如：
Accident can happen on such rainy days;
这样的多雨天气有可能会发生事故;客观的可能性
Peter may come with us tonight,but he isn’t sure yet;
彼得今晚可能和我们来,但他还没确定;实际可能性,不用can
2.表示具体事情实际发生的可能性：
1表示具体事情实际发生的可能性的层次比较
词形 | 肯定式 | 否定式 | 疑问式 |
must | 必定,必然 | / | / |
will | 很可能,大概 | 不会,不该 | 会……吗 |
would | 可能性比will小 | 新盖中盖语气比won’t弱 | 语气比will弱 |
should | 说话者有较大的试探性 | / | / |
ought to | 说话者有较大的试探性含义同should | / | / |
can | / | 不可能 | 有可能吗 |
could | 可疑的可能 | 不可能 | 语气比can弱 |
may | 或许,也许,也未可知,也说不定 | 可能不 | / |
might | 比may还弱 | 比may not还弱 | / |
| | | |
2表示具体事情实际发生的可能性时,may,must常用于肯定句,一般不用于否定句和疑问句may not表示“可能不”；can常用于否定句、疑问句或感叹句中,表示疑惑、惊讶或不相信等意思；could既可用于肯定句,又可用于否定句、疑问句中;如：
This can’t/ couldn’t be done by him;表不相信
这不可能是他做的;
This may not be done by him;表不确定
这可能不是他做的;
He could be on his way home now;could不如may/ might常用
他现在可能在回家的路上;
Can this be done by him表示疑惑、惊讶
这可能是他做的吗
Mr. Bush is on time for everything;How can it be that he was late for the opening ceremony表示疑惑、惊讶
布什先生做每件事都很按时;他怎么可能在开幕仪式上迟到呢
I didn’t hear the phone;I must have been asleep;表肯定
我没听到电话;我肯定已经睡着了;
3.would,could,might并不一定与过去时间有关,而是表示可能性弱于他们相应的现在时形式;另外should也不一定与过去时间有关;如：
This may/ might be done by him;后者比前者语气弱
这件事有可能是他干的;
4.should/ ought to表推测时,表示说话者有较大的试探性;如：
He ought to/ should be here on time—he started early enough;
他应该按时到这里——他出发的够早的;
We should arrive before dark;
我们按说能在天黑前到达;
The roads should be less crowded today;
今天路上应该不至于那么拥挤了;
傻事
（三）表请求、允许、允诺
1.当对方是决策者时,你代表你们自己I,we或代表第三者he,she,they向对方you请示或提出建议时用：①Shall Iwe…②Shall he/ she/ they…③Would/ Will you…如：
Shall we begin our class
Shall the driver wait outside
When shall my father be able to leave hospital
Would you do me a favor
2.could/ might/ would/ should表委婉语气的功能;如：
—Could/ Might I u your bike tomorrow morning
夫妻关系如何经营—Yes,you can/ may;否定：No,I’m afraid not;
不可以说,Yes,you could/ might;回答允许时,用could/ might表委婉是不恰当的;如：
—Could I borrow your dictionary
—Yes,of cour you can;
3.当你自己I是决策者,给对方you或第三者he,she,they以命令、警告、允诺或威胁时,要用shall;此外,当宣布法律、规定时,也要用shall;如：
You shall leave the room at once,and he also shall;= I order you and him to leave the room at once;
你马上给我滚出去他也一样;说话者的意志
It has been announced that candidates shall remain in their ats until all the papers have been collected;
通知称在所有试卷收上来之前,应试者必须留在座位那里;规则或规定
（四）表必要性
1.must常用来表示必要性,意为“必须”;表示现在或将来必须做某事用“must + 动词原形”；表示现在或将来不必做某事时,用don’t have to do sth. 或don’t need to do sth. 或needn’t do sth.；表示过去没必要做某事时,分为以下情况：①当表示过去没必要做某事,但事实上却做了,用needn’t have done sth.；②当表示过去没必要做某事,而不涉及是否已经做了,可用didn’t have to do sth. 或didn’t need to do sth. 或It was not necessary to do sth.等;如：
You needn’t have worded that late last night;It was harmful to your health;
你昨晚本不必工作到那么晚,那对你的身体不好;
—
Did you work very late last night
—No,I didn’t;I didn’t need to work very late;
——您昨天晚上工作到很晚了吗
——不是很晚,我没必要工作到很晚;
2.should也可以表示必要性,意为“义务上应该”;should表必要性时,在语气上比must必须弱;“should + 动词原形”表示现在或将来应该做某事的必要性；“should + have + 过去分词”表示过去本该做某事的必要性;如：
I should go and visit him this afternoon,but I wonder if I will be free;
今天下午我应该去看望他,但我不知道我是否有空;表示将来的必要性
You should have come to the conference yesterday;What was the reason for your abnce
你昨天应该参加那个会议;你缺席的原因的是什么表示过去的必要性
（五）“情态动词 + have done”用法一览表
情态动词 + 完成式 | 意义 | 惩戒的意思 例句 |
must have done | “想必/准是/一定做了某事”,否定式为can’t/ couldn’t have done | It must have rained last night,for the road is quite muddy; The lights were off;They must have been asleep; |
can/ could have done | ①“本来能够……” ②“过去可能会……” | Can he have gone to his aunt’s You could have come 5 minutes earlier; |
can/ could not have done | ①“过去不可能……” ②“过去没能……” | I saw Mr. Wang just now;He couldn’t have gone to Beijng; |
may/ might have done | “也许/或许已经……”;一般只用于肯定句和否定句中在否定句中表示“可能不”,不用于疑问句;用might则表示语气更加不肯定; | It’s too late;I think he may have gone to bed; He may not have finished the work; She might have caught a cold; |
should/ ought to have done | “本该做某事,而实际上未做” | You should have come to the meeting earlier; You ought to have done this exerci more carefully; |
shouldn’t/ ought not to have done | “本不该做而做了某事” | You shouldn’t have told her the truth; |
needn’t have done 台儿庄古城 | 表示“做了本来不必去做的事”;注意：didn’t need to do表示“没必要做并且实际上也没有做某事”; | You needn’t have taken a taxi here,for it was very near to my hou; I didn’t need to clean the windows;My brother did it; |
had better have done | 用于事后的建议,含轻微责备的口吻,意为“要是当时做了某事就好了”,其否定式had better not have done表达相反的含义; | You had better have started earlier; You had better not have scolded her; |
would rather have done | 表示“宁愿当时做某事”,其否定式would rather not have done表达相反的含义,两者都表示“后悔”之意; | I would rather have taken his advice; I raid objections at the meeting,but now I would rather not have done that; |
would like/ love to have done | 表示过去愿意做某事,但未做成; | I would love to have gone to the party last night but I had to work extra hours to finish a report; |
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（六）情态动词其他用法要点
1.cannot but + do sth.表示“不得不,只好”;如：
I cannot but choo to go;
我只好去;
2.may well和may as well结构
1“may well + 动词原形”是一种常用结构,意为“完全能,很可能”,相当于to be very likely to;如：
He may well be proud of his son;
他大可为儿子感到自豪;
Her appearance has changed so much that you may well not recognize her;
她的模样变化太大,你很可能认不出她了;
2“may/ might as well + 动词原形”意为“最好,满可以,倒不如”,相当于had better或to have no strong reason not to;如：
You may as well do it at once;
你最好马上就做这件事;
You may as well stay where we are;
我们留在现在的地方倒也不错;
3.can not或never等否定词与enough连用表示“再……也不为过”;具体用法见形容词、副词专题;
4.may可以用于祈使句,表示祝愿;如：
May才鱼 we never forget each other;
愿我们彼此永不相忘;
May you return in safety;
愿你平安归来;
5.Why/ How + should结构表示说话人对某事不能理解、感到意外、惊异等,意为“竟会”;如：
Why should you be so late today
你今天来的怎么这么晚
How should I know
我怎么会知道意为：我不知道;
6.must表示“偏要、硬要”做某事;如：
—How old are you,madam
—If you must know,I’m twice my son’s age;
>护理老人的保姆
