2024屆高考英語一輪語法專題復習學案：第1部分 專題3 情態動詞和虛擬語氣（新人教版）
◆情態動詞的核心考點
1．can，be able to 和could
(1)can和be able to都表示能力，意思上沒多大區別。但can只有現在和過去時，而be able to則有更多的形式。但當成功地完成某一具體動作時，通常不用could而用was/were able to來表示。這時was/were able to 相當于managed to，表示經過一番努力，終于能夠完成某事。
Her mother can speak French.
The wounded man was still able to get to the village and was saved by the villagers in the end.
(2)表示猜測“可能”，一般用于疑問句和否定句。
—Can the news be true?
—It can’t be true.
Someone is knocking at the door.Who could it be?
(3)can可以表示理論上的可能性，指常有的行為或情形，意為“有時會……”。
Anybody can make mistakes.
(4)表示請求、允許(表請求時，口語中常用could代替can使語氣更委婉，回答時用can)。
Can I go now?
—Could I come to see you tomorrow?
—Yes，you can.(否定答語可用No，I’m afraid not.)
(5)表示驚異、懷疑、不相信的態度(主要用于否定句、疑問句或感嘆句中)。
How can that be true？I can’t believe my eyes and ears.
How could you be so careless?
(6)can的特殊用法。
can but只有；can’t but不得不；can’t...too再怎樣也不為過，越……越好
I can but wait.
I can’t but wait.
You can’t be too patient to the customers.
2．may和might的用法
(1)表示允許、請求，might比may的語言更委婉一些。
—May I watch TV now?
—Yes，you may.(Yes，please.)
—No，you mustn’t.(No，you’d better not.)
(2)表示可能性時，might比may的可能性小，may表示的可能性比can小(主要用于陳述句、肯定或否定句，疑問句用can代替)。
The story may not be true.
(3)表示祝愿(不用might)
May you succeed!
(4)may/might as well最好還是……，不妨
You might as well do it now.
(5)may/might well很可能
He may well be late for class.
3．must，have to和ought to的用法
(1)must
①表示“必須，應該，一定要”。強調主觀看法，只有現在時形式，否定式是must not(mustn’t)。must開頭的問句，其否定回答要用needn’t或don’t have to代替。
②表示必然的結果。
All men must die.
③還可表示主語固執、偏要做他人不希望做的事。
It can’t help；he must do that.
(2)have to著重客觀需要，能用于更多時態(過去時或將來時)。
He will have to be there before ten.
(3)ought to表示義務和責任，“應該”，比should語氣要強。
You ought to take care of yourself.
4．need和dare的用法
(1)need表示“需要，必要”，只能用于否定句和疑問句。在肯定句中，常用must和have to代替。
(2)dare表示“敢”，通常用于否定句、疑問句和條件狀語從句中。
Dare you go home alone at eleven in the evening?
(3)need和dare的特殊用法
①need表“需要”時，可用want，require代替。
The desk needs to be repaired./The desk needs repairing.
②dare作實義動詞時，在肯定句中要接to，在疑問句和否定句中to可省去。
He dares to catch a snake.
I do not dare (to) complain.
Do you dare (to) swim in the river?
5．will和would的用法
(1)will
①表示請求、建議，常用于第二人稱。
Will you please go with me?
②表示意愿、決定、允許。
I will never do that again.
③表示習慣性動作或某種傾向，“總是，慣于”，通常用于第三人稱。
Rosa will always be late for school.
(2)would
①表示請求、建議，比will委婉，指現在時間，多用于第二人稱。
Would you like a cup of tea?
②表示過去習慣性動作或某種傾向。
We would play badminton on Sundays.
6．shall和should的用法
(1)shall
用于第一、三人稱，在問句中表示征求對方意見或請求。
Shall I come in?
用于第二、三人稱的陳述句中，表示命令或威脅。
You shall do as your father says.
(2)should
①表示責任、義務，意為“應該”。
②表示驚訝語氣，意為“竟然”。
You should wear slippers in class.
③用于條件句，表示“假如，萬一”，省去if，should可提至句首。
Should you be late，apologize to the teacher.
7．情態動詞表示推測或判斷的用法
下表即是表示推測的情態動詞使用的場合：
情態動詞 對現在和未
來的推測 對過去
的推測 使用場合
must must＋do must have done 肯定句
may/might may/might＋do may/might have done 肯定句、否定句
can/could can/could do can/could have done 否定句、疑問句(could可用于肯定句)
should 用來表示一種估計的情況“按理會/估計會”should do should have done 肯定句、否定句、疑問句
情態動詞＋have done的用法
(1)should have done表示“本來應該做某事而實際上未做”，而shouldn’t have done則表示“本不應該做某事而實際上做了”。
You should have told me about it earlier.
You shouldn’t have said such words to your parents.
(2)ought to have done也表示“本應該……”，而ought not to have done則意為“本不應該……”。
You ought to have told me about it earlier.
You ought not to have said such words to your parents.
(3)needn’t have done表示“本無必要做某事而實際上做了”。
You needn’t have walked so quickly since time was enough.
(4)could have done表示“本來有可能……而事實上未做到”。
I could have come on time，but my car broke down on the way.
(5)may/might have done表示“過去可能發生過某事”或“本來應該或可以做某事(實際上沒做)”。
You might have given him more help，but you were so busy.
◆虛擬語氣的核心考點
1．虛擬語氣用于條件狀語從句
(1)表示與現在事實相反的假設，條件狀語從句中的謂語動詞用一般過去時(be動詞用were)，而主句中的謂語動詞用“would/should/could/might＋動詞原形”。
If I were you，I would buy that house.
If he had time，he should go with you.
(2)表示與過去的事實相反，條件狀語從句中的謂語動詞用過去完成時，主句中的謂語動詞則用“would/should/might/could＋have＋過去分詞”。
If he had taken my advice，he would have succeeded in passing the examination.
(3)表示與將來事實相反，條件狀語從句中的謂語動詞用一般過去時或“should/were to＋動詞原形”，而主句中的謂語動詞則用“would/should/could/might＋動詞原形”。
If it were to rain tomorrow，the football match would be put off.
(4)當條件狀語從句表示的行為和主句表示的行為所發生的時間不一致時，動詞的形式要根據它所表示的時間作相應調整。
If they had worked hard，they would be very tired now.(從句說的是過去，主句指的是現在)
2．虛擬語氣用于名詞性從句
(1)虛擬語氣在賓語從句中的運用。
①“wish＋賓語從句”表示不能實現的愿望，譯為“要是……就好了”等。表示現在不能實現的愿望，從句中的謂語動詞用一般過去時；表示將來不能實現的愿望，從句中的謂語動詞用“would/could＋動詞原形”；表示過去不能實現的愿望，從句中的謂語動詞用“had＋過去分詞”或“could/should＋have＋過去分詞”。
I wish it were spring all the year round.
I wish I had known the answer.
I wish I could fly like a bird.
②在表示建議、要求、命令等動詞后的賓語從句中，謂語動詞用“should＋動詞原形”，should可以省略。
常見的動詞有：suggest，advise，propose，demand，require，insist，request，command，order等。
She suggested we (should) leave here at once.
The doctor ordered she should be operated on.
(2)虛擬語氣在同位語從句和表語從句中的運用。
表示建議、要求、命令等的名詞，如advice，idea，order，demand，plan，proposal，suggestion，request等，其后的表語從句和同位語從句中謂語動詞用“(should＋)動詞原形”，should可以省略。
His suggestion that we (should) go to Shanghai is wonderful.
My idea is that they (should) pay 100 dollars.
(3)虛擬語氣在主語從句中的運用。
在主語從句中，謂語動詞的虛擬語氣用“(should＋)動詞原形”的結構，表示驚奇、不相信、理應如此等。
It is necessary (important，natural，strange，etc.)that we (should) clean the room every day.
It was a pity (a shame，no wonder，etc.)that you (should) be so careless.
It will be desired (suggested，decided，ordered，requested，proposed，etc.)that she (should) finish her homework this afternoon.
注意：這種從句表示的是事實。如果人對這種事實表現出驚奇的情感，就可用虛擬語氣；反之，如果不表示驚奇等情感，that從句也可用陳述句語氣。
It is a pity that you can’t swim.
3．虛擬語氣在其他場合的運用
(1)虛擬語氣在as if/as though，even if/even though等引導的表語從句或狀語從句中，如果從句表示的動作發生在過去，用過去完成時；指現在狀況，則用一般過去時；指將來狀況則用過去將來時。
He did it as if he were an expert.
Even if she were here，she could not solve the problem.
(2)虛擬語氣用于定語從句中。
這種從句常用于句型“It is (high)time (that)．..”中，定語從句的謂語動詞用一般過去時(be用were)或“should＋動詞原形”，意為“(現在)該……”。
It’s time that I picked up/should pick up my daughter.
It’s high time we were going/should go.
(3)虛擬語氣用在if only引導的感嘆句中。
If only I were a pilot.
If only I had taken his advice.
(4)虛擬語氣在一些簡單句中的運用。
①情態動詞的過去式用于現在時態時，表示說話人謙虛、客氣、有禮貌或語氣委婉，常出現在日常會話中。
It would be better for you not to stay up too late.
Would you be kind enough to close the door?
②用于一些習慣表達法中。
Would you like a cup of tea?
I would rather not tell you.
◆情態動詞、虛擬語氣與語法填空
對于情態動詞在語法填空中考查主要注意情態動詞的一般用法以及“情態動詞＋have done”；而對于虛擬語氣的考查除了注意情態動詞的選用，還需注意一般過去時與過去完成時在虛擬語氣中的考查。
典題試做1
在空白處填入適當的情態動詞或括號內所給動詞的正確形式
1．You
be Carol.You haven’t changed a bit after all these years.(2024·重慶)
答案 must
解析 根據be動詞為原形，可判斷此處缺少情態動詞或助動詞。根據后句You haven’t changed a bit 可知，說話者完全認出了Carol，猜測的語氣非常肯定，故填must。
2．You
feel all the training a waste of time，but I’m a hundred percent sure later you’ll be grateful you did it.(2024·陜西)
答案 may
解析 由句中的but及后一分句中的a hundred percent sure可知，此處表示語氣不強烈的推測，故填may。
3．Although you
find bargains in London，it’s not generally a cheap place to shop.(2024·大綱全國)
答案 can
解析 由語境可知，此處表示“你可能在倫敦找到便宜貨”，指客觀上的可能性。故填can。
4．Mum：Are they there? Oh，my goodness.I
have put them in there when the phone rang.(2024·新課標全國樣卷)
答案 must
解析 動詞原形前常跟情態動詞或助動詞。根據句意，是對過去的推測，故肯定句中用must have done形式。
5．—Sorry，Mum! I failed the job interview again.
—Oh，it’s too bad.You
have made full preparations.(2024·福建)
答案 should
解析 表示“本應該做某事，但事實上卻沒有做”，用should have done sth.表示，故填should。
6．I still remember my happy childhood when my mother
take me to Disneyland at weekends.(2024·四川)
答案 would
解析 由主句中的關鍵信息 my happy childhood可知，是小時候經常被帶去迪斯尼樂園。表示“過去常常”要用情態動詞would。
7．He walked in as if he
(buy) the school.And the word quickly got around that he was from New York City.(2024·廣東)
答案 had bought
解析 這是由as if引導的虛擬語氣，因為是與過去事實相反，故用過去完成時。
8．No one
be more generous；he has a heart of gold.(2024·天津)
答案 can/could
解析 “No one could be more generous”是否定詞和比較級連用，表達最高級含義，can/could可以在否定句中表示推測。
9．Ellen is a fantastic dancer.I wish I
(dance) as well as her.(2024·陜西)
答案 danced
解析 wish后跟賓語從句時，從句中需要用虛擬語氣，主句用一般現在時，從句中用did表示對現在事實的虛擬。故填danced。
10．It is lucky we booked a room，or we
(have) nowhere to stay now.(2024·安徽)
答案 would have
解析 or引導含蓄虛擬條件句，or后面是主句，相當于if we hadn’t booked a room，we would have nowhere to stay now，根據“now”可知，是對現在進行虛擬。故填would have。
