2024屆高三英語一輪語法專項學案：第7節 情態動詞和虛擬語氣
第七節 情態動詞和虛擬語氣
(對應學生用書第252頁)
考點一 情態動詞的基本用法
1．can的用法
(1)表示能力。需注意的是，could表示過去一般的能力，而was/were able to表示有能力而且成功地做成了某事。
The fire spread through the building very quickly, but everyone was able to get out.盡管這場大火迅速蔓延了整個大樓，但是每個人都逃了出去。
(2)表示理論上的可能性，意為“有時候可能會”。
Everything can happen, everything is possible and probable.
任何事情都有可能發生， 沒有什么是不可能的。
(3)表示請求和允許。在問句中，could比can語氣要委婉。
—Could I use your bike? 我可以用你的自行車嗎？
—Of course you can. 當然可以。
(4)表示推測，常用于疑問句和否定句。
What can they be doing there?
他們可能正在那里干什么？
He can't be in the classroom, for the light has been turned off. 他不可能在教室，因為燈已關了。
(5)can't/never ... too/enough表示“再……也不為過”。
You can never be too careful while driving a car. 開車時再小心都不為過。
2．may的用法
(1)表示請求、允許，此時might比may的語氣更委婉。
—May/Might I play basketball this afternoon?
今天下午我可以打籃球嗎？
—No, you may not. 不，不行。
(2)表示推測意為“可能、或許”。
We may go to the cinema tonight, but we are not sure yet.我們今晚或許去看電影，但還未確定。
(3)用于祈使句中表示祝愿。
May you be happy every day and succeed in your work! 祝你每天都過得開心且工作順利！
(4)“may as well＋動詞原形”意為“最好，倒不如”。
There is nothing to do, so I may as well go to bed. 沒什么事可做， 我還是上床睡覺好了。
3．must的用法
(1)表示“必須；應該”，must一般指主觀，而have to指客觀表示“不得不”。
We must do everything step by step.
我們一切都必須循序漸進地做。
I have to go now for I've a meeting 15 minutes later.我必須走了，因為15分鐘后有個會。
(2)表示推測意為“一定會”，此時不能用于否定句。
He must be ill. He looks so pale.
他一定病了，他的臉色蒼白。
(3)mustn't表禁止，而have to的否定式意為“不必”。
Smoking mustn't be allowed in the office.
辦公室里不許吸煙。
—Must we hand in our exercise today?
我們今天必須交作業嗎？
—No, you don't have to. 不，不必今天交。
(4)表示偏執、固執意為“偏要，硬要”。
If you must smoke, please go out.
如果你硬要吸煙，那就出去吧。
4．shall的用法
(1)用于第一、三人稱的疑問句中，用于征求對方的意見。
Shall I buy some picture books for the children? 要我給孩子們買些圖畫書嗎 ?
(2)用于第二、三人稱的陳述句，表示說話人給對方的命令、警告、允諾或威脅；此外，當頒布法律、規定時也用shall。
You shall finish your homework first before you go out and play. 你得先做完作業再出去玩。
5．should的用法
(1)表示勸告和建議，意為“應該”。此時ought to比should語氣要強。
You should/ought to put more effort into your work.你應該更加努力地工作。
(2)表示預測可能性，意為“按道理應該會”。
He left Paris in the morning. So he should arrive here by supper time.
他早上離開巴黎， 因此他晚飯前應該能到。
(3)表示驚訝、意外等情緒，意為“竟然”。
It is strange that such things should happen in our school.真奇怪，這樣的事情竟然在我們學校發生了。
6．will/would的用法
(1)表示意愿，可用于各種人稱。
We will never give up working, whatever happens. 無論發生什么事，我們都不會放棄工作。
(2)表示“請求；建議”，此時would比will更委婉。
Would you come into the bar and have a drink with me? 你愿意進酒吧和我喝一杯嗎 ?
(3)表示習慣，意為“總是，習慣于”。與used to相比，would表示過去重復、習慣性動作；而used to則強調過去與現在的對比。
Last year our English teacher would tell us stories in English after class. 去年我們的英語老師常常課后給我們用英語講故事。
He used to spend all his money on food and drink; now he lives a simple life.
他過去把錢都花在吃喝上， 現在可節省了。
7．need/dare的用法
need和dare既可作實義動詞又可作情態動詞，用作情態動詞時，主要用于疑問句和否定句。
You needn't worry about him. 你不必為他擔心。
She dare not go out alone at night.
她晚上不敢一個人出去。
考點二 “情態動詞＋have done”的用法
類型 構成
主要用法
表示對
過去的
推測 must have done 表示對過去發生的事情十分肯定的推測，意為“想必/準是/一定做過某事”。
can/could
have done 多用于否定句和疑問句，表示對過去發生的行為的懷疑和不肯定，意為“不可能已經……”或“可能已經……了嗎？”。
may/might
have done 用于肯定句和否定句，表示對過去發生某事的可能性的推測，意為“或許做過某事”或“或許沒做過某事”。
表示后
悔、責備
或遺憾 can/could
have done
用在肯定句中，表示對過去沒有實現的可能性的遺憾，意為“本來能做……實際上卻未做”。
should/ought
to have done 表示本該做某事而實際上未做；否定式表示本不該做但卻做了。
needn't have
done 表示做了本來不必做的事。
The accident must have happened at about 11 o'clock in the morning.
事故一定是發生在上午11時左右。
He can't have gone to Shanghai, for I saw him a minute ago.
他不可能去了上海， 因為我剛才還看見他。
He might have said so at the meeting, but I'm not sure.他或許在會上說過這樣的話，但我不確定。
You could have done better, but you didn't try your best.你本來能做得更好，但你沒盡全力。
I was really anxious about you.You shouldn't have left home without a word.
我真的為你擔心，你本不該不打聲招呼就離開家。
You needn't have told him the news; he knew it already.
你不必再告訴他這個消息， 他已經知道了。
考點三 虛擬語氣在非真實條件句的用法
說明 if從句謂語動詞 主句謂語動詞
與現在事
實相反 動詞的過去式(be用were) would/should/ could/might＋動詞原形
與過去事
實相反 had＋過去分詞 would/should/ could/ might＋have＋過去分詞
與將來事
實相反 動詞的過去式(be用were)/should＋動詞原形/were to＋動詞原形 would/should/ could/ might＋動詞原形
If I were you, I would take action right away.
如果我是你，我會立即采取行動。
If you had got up earlier, you would have caught the train. 如果你早點起床， 你就會趕上火車了。
If you should fail, what would you do?
萬一你失敗了， 你準備怎么辦？
考點四 虛擬條件的三種特殊形式
1．省略if的虛擬語氣
如果if從句中含有were/had/should，則可以把if省略，把這三個詞置于句首形成倒裝。
Were it Sunday tomorrow, we should go to the Great Wall.
要是明天是星期日， 我們就能去長城了。
2．錯綜時間條件句
如果虛擬條件句的動作與主句動作發生的時間不一致，這時被稱作錯綜時間條件句，動詞的形式應根據它們各自表示的時間做出相應的調整。
If you had prepared in advance, you wouldn't be in such an awkward position now.
如果你事先做好準備， 現在就不至于那么被動。
3．含蓄虛擬條件句
有時假設的情況不是以if條件從句表示，而是通過其他形式表現出來，這時被稱作含蓄虛擬條件句，其用法主要有三。
(1)用but for，without等介詞(短語)表示條件。
But for the rain we should have had a pleasant journey.要不是下雨， 我們會有一次愉快的旅行。
(2)用連詞otherwise，or等暗示后文與前面的情況相反，從而引出后文的虛擬語氣。
There was a traffic jam on the way，otherwise I would have arrived an hour ago.
路上堵車， 要不然我一小時前就到了。
(3)虛擬條件通過but暗示出來，but前面為虛擬語氣，后面為真實情況。
I should have given you more help, but I was too busy.我本該多幫幫你，但我太忙了。
考點五 虛擬語氣的其他情況
1．用于賓語從句中
(1)wish后的虛擬語氣
wish后賓語從句的虛擬語氣有三種表達方式：
?、龠^去時→表現在；②過去完成時→表過去；
③could/would/might＋動詞原形→表將來。
I wish he were with us at this special moment.
我希望這個特殊時刻他和我們在一起。
How I wish I had followed my parents' advice.
我多么希望聽了父母的建議。
She wished she would be admitted to Beijing University this year.她希望今年能被北大錄取。
(2)用于表示要求、命令、建議、意圖、決定、推薦等意義的動詞：suggest, advise, propose, command, request, insist, recommend等后接賓語從句時，從句謂語動詞為(should＋)動詞原形。
He demanded that he (should) be told everything. 他要求將一切告訴他。
【點津】 當suggest表示“暗示，表明”，insist表示“堅持認為，堅持說”時，從句要用陳述語氣。
Jane's pale face suggested that she was ill and we suggested that she (should) have a medical examination. 簡蒼白的臉色表明她病了，我們建議她做一下醫學檢查。
(3)would rather后的賓語從句，謂語用一般過去時表現在或將來要做的事情，用過去完成時表示過去的動作。
I'd rather that you came tomorrow.
我寧愿你明天來。
I'd rather that you had come yesterday.
你昨天來了該有多好。
2．用于主語從句、表語從句和同位語從句中
(1)表示要求、命令、建議、意圖、決定、推薦等意義的動詞，構成it is ＋動詞的過去分詞＋ that ...時，that從句中的謂語動詞用(should＋)動詞原形。
It is advised that the meeting (should) be put off until next week.有人建議會議推遲到下周舉行。
(2)表示要求、命令、建議、意圖、決定、推薦等意義的名詞，如suggestion，proposal，advice，order，request等后面的表語從句和同位語從句中，謂語動詞用(should＋)動詞原形。
My request is that you (should) make an apology to your teacher.
我的要求是你要向你的老師道歉。
We all agreed to his suggestion that we (should) go out for picnic.我們都同意他的建議去野餐。
3．用于定語從句中
It's (high/about) time (that) ...句型中，從句的謂語動詞用一般過去時或should＋動詞原形(其中should不可省略)，句意為“確實到了……的時候了”。
It is high time that we took some measures to solve the problem.
確實到了我們該采取措施解決問題的時候了。
4．用于as if引導的從句中
表示與現在事實相反用一般過去時；表示與過去事實相反用過去完成時。
People treat him as if he were a dangerous person.人們把他看作是一個危險人物。
He talks as if he had been to many countries.
他說起話來好像他去過好多國家似的。
5．用于if only引導的感嘆句中，其用法相當于wish后的賓語從句。
He failed in the exam again. If only he had worked harder.
他考試又失敗了。要是他早努力些就好了。
(對應學生用書第255頁)
?、?從下面方框中選擇恰當的情態動詞填空
shall，must，can，could，may，would，ought to，might，should1.________ you get a good result in your experiment!
2．________ you rather live in a town，or in the country?
3．________ we go to the new restaurant to have dinner?
4．You ________ leave your key at the reception desk.
5．A computer can't think itself.It ________ be told what to do.
6．The question comes down to whether we ________ act upon his advice.
7．Hurry up！He ________ be waiting for us anxiously right now.
8．My MP5 has disappeared.Who ________ have taken it?
9．—Where is Bob?
—He ________ be in the living room，but I am not sure.
10．You ________ not have told her the terrible news.She is very upset right now.
11．They are playing basketball；they ________ have finished their homework.
12．I saw him just now so he ________ not have gone abroad.
13．It's surprising that such a gentleman ________ be so rude to the old.
14．—May I watch TV after supper?
—No，you ________．
15．You look tired，so you ________ as well go and have a rest.
【答案】 1.May 2.Would 3.Shall 4.may/can 5.must 6.ought to/should 7.must 8.can/could
9．may/might/could 10.should 11.must
12．could 13.should 14.mustn't 15.may/might
Ⅱ.根據所提供的情景，用適當的情態動詞完成句子
1．Marie called me up last night but I didn't hear it.I ________________________ asleep.
