高考考點之情態動詞
情態動詞主要用來表示說話人的看法、態度等，它在英語動詞中屬於最難把握的一類。接下來，小編給大家準備了 高考考點之情態動詞,歡迎大家參考與借鑑。
情態動詞，屬於助動詞的一種。首先我們來看看助動詞。
概 說
助動詞(auxiliary)主要有兩類：基本助動詞(primary auxiliary)和情態助動詞(modal auxiliary)。基本助動詞有三個：do, have和be;情態助動詞有十三個：may, might; can, could; will, would; shall, should; must, need, dare1, used to, ought to. 上述兩類助動詞的共同特徵是，在協助主動詞構成限定動詞詞組時，具有作用詞的功能：
1) 構成否定式：
He didn't go and neither did she.
The meeting might not start until 5 o'clock.
2) 構成疑問式或附加疑問式：
Must you leave right now?
You have been learning2 French for 5 years, haven't you?
3) 構成修辭倒裝：
Nowhere can he obtain3 any information about his sister.
Hardly had he arrived when she started complaining.
4) 代替限定動詞詞組：
A: Who can solve this crossword4 puzzle?
B: Tom can.
A: Shall I write to him?
B: Yes, do.
情態助動詞的特徵
基本助動詞與情態助動詞最主要的區別之一是，基本助動詞本身沒有詞義，而情態助動詞則有自己的詞義，能表示說話人對有關動作或狀態的看法，或表示主觀設想：
What have you been doing since? (構成完成進行體，本身無詞義)
I am afraid I must be going. (一定要)
You may have read some account5 of the matter. (或許已經)
除此之外，情態助動詞還有如下詞法和句法特徵：
1) 除ought和used以外，其他情態動詞後面只能接不帶to的不定式。如果我們把ought to和used to看做是固定詞組的話，那麼，所有情態動詞無一例外地只能接不帶to的不定式：
We used to grow beautiful roses.
I asked if he would come and repair my television set.
2) 情態助動詞在限定動詞詞組總總是位居第一：
They need not have been punished so severely6.
3) 情態助動詞用於第三人稱單數現在時的時候，沒有詞形變化，即其詞尾無-s形式：
She dare not say what she thinks.
4) 情態動詞沒有非限定形式，即沒有不定式、-ing分詞和-ed分詞形式：
Still, she needn't have run away.
5) 情態助動詞的“時”的形式並不是時間區別的主要標誌。在不少場合，情態助動詞的現在時和過去時形式都可以表示現在、過去或將來時間：
Would you mind very much if I ask you to do something?
She told him he ought not to have done it.
6) 情態助動詞之間是相互排斥的，即在一個限定動詞詞組中只能出現一個情態助動詞，但有時卻可以與have和be基本助動詞連用：
You should have washed the wound7.
Well, you shouldn't be reading a novel.
現將情態助動詞的各種形式列表如下：
情態助動詞的意義和用法
情態助動詞從最普通的意義上來說，是修飾分句意義的一種方式，它可以反映說話者對其表述是否真實和可能的程度作出判斷。但不同的情態助動詞本身所包含的意義和用法又不同，下面逐個分析。
1) can和could的用法
1. 表示能力或客觀可能性，還可以表示請求和允許。如：
Can you finish this work tonight?
Man cannot live without air.
— Can I go now? — Yes, you can.
注意：①could也可表示請求，預期委婉，主要用於疑問句，不可用於肯定句，答語應用can(即could不能用於現在時態的簡略答語中)。如：
Could I come to see you tomorrow?
Yes, you can. (否定答語可用No, I'm afraid not.)
②can表示能力時，還可用be able to代替。如：
I'll not be able to come this afternoon.
2. 表示驚異、懷疑、不相信的態度。(主要用在否定句、疑問句或驚歎句中)
Can this be true?
How can you be so careless!
This cannot be done by him.
3. “can(could) + have + 過去分詞”的疑問或否定形式表示對過去發生的行爲懷疑或不肯定。如：
He cannot have been to that town.
Can he have got the book?
2) may和might的用法
1. 表示許可。
表示請求、允許時，might比many的語氣更委婉一些，否定回答時要用mustn't表示“不可以”、“禁止”、“阻止”之意。如：
You may drive the car.
— Might I use your pen? — No, you mustn't.
用May I ... 徵詢對方許可在文體上比較正式，在口氣上比較客氣。在日常口語中，用Can I ... 徵詢對方意見在現代口語中更爲常見。
2. 用於祈使句中表示祝願。如：
May you succeed!
3. 表示推測、可能(疑問句不能用於此意)。
He may be very busy now.
4. “may(might) + have + 過去分詞”表示對過去發生的行爲的推測。如：
He may not have finished the work.
3) must和have to的用法
1. 表示必須、必要。如：
You must come in time.
回答must引出的問句時，如果是否定的回答，不能用mustn't，而要用needn't或don't have to。
— Must we hand in our exercise books today?
— Yes, you must. (No, you don’t have to.)
2. “must be + 表語”的結構表示推測，它的否定或疑問式用can代替must。
This must be your pen.
3. “must + have + 過去分詞”的結構常用在肯定句中，表示對過去發生的行爲的推測。它的否定或疑問式用can代替must。
He must have been to Shanghai.
4. have to的含義與must相似，兩者往往可以互換使用，但have to有各種形式，隨have的變化而定。must與have to有下列幾點不同：
① must表示的是說話人的主觀看法，而have to則往往強調客觀需要。如：
The play is not interesting. I really must go now.
I had to work when I was your age.
② must一般只表現在，have則有更多的時態形式。
③ 二者的否定意義不大相同。如：
You mustn't go. 你可不要去。
You don't have to go. 你不必去。
④ 詢問對方的意願時應用must。如：
Must I clean all the room?
4) dare和need的用法
1. need表示“需要”或“必須”，作情態動詞時，僅用於否定句或疑問句中，在肯定句中一般用must, have to, ought to,或should代替。如：
You needn’t come so early.
— Need I finish the work today?
— Yes, you must.
注意：needn't + 不定式的完成式“表示本來不必做某事而實際上做了某事”。如：
You needn't have waited for me.
2. Dare作情態動詞時，主要用於疑問句、否定句和條件從句中，一般不用在肯定句中。如：
How dare you say I'm unfair.
He daren't speak English before such a crowd, dare he?
3. Dare和need常用作實義動詞，有時態、人稱和數的變化，所不同的是，作實義動詞時，在肯定句中，dare後面通常接帶to的不定式，在否定和疑問句中，dare後面可接帶to或不帶to的不定式。如：
I dare to swim across this river.
He does not dare (to) answer.
Don't you dare (to) touch it!
I wondered he dare (to) say that.
He needs to finish it this evening.
5) shall和should的用法
1. Shall用於第一人稱，表示徵求對方的意願。如：
What shall we do this evening?
2. Shall用於第一、第三人稱疑問句中，表示說話人徵求對方的意見或向對方請示。如：
Shall we begin our lesson?
When shall he be able to leave the hospital?
3. Shall用於第二、第三人稱，表示說話人給對方命令、警告、允諾或威脅。如：
You shall fail if you don't work harder. (警告)
He shall have the book when I finish reading. (允諾)
He shall be punished. (威脅)
4. Should表示勸告、建議、命令，其同義詞是ought to;在疑問句中，通常用should代替ought to。如：
You should go to class right away.
Should I open the window?
Should的含義較多，用法較活，現介紹三種其特殊用法。請看下面的句子：
① I should think it would be better to try it again. 我倒是認爲最好再試一試。
② You are mistaken, I should say. 依我看，你是搞錯了。
③ I should advise you not to do that. 我倒是勸你別這樣做。
④ This is something I should have liked to ask you. 這是我本來想問你的。
從以上例句可以看出：情態動詞should用於第一人稱時可以表示說話人的一種謙遜、客氣、委婉的語氣。
Should還可以用在if引導的條件從句，表示一件事聽起來可能性很小，但也不是完全沒有可能。相當於“萬一”的意思。從句謂語由should加動詞原形構成，主句謂語卻不一定用虛擬語氣。如：
⑤ Ask her to ring me up if you should see her. 你萬一見到她，請讓她給我打個電話。
⑥ If you should change your mind, please let us know. 萬一你改變主意，請通知我們。
⑦ Should I (If I should) be free tomorrow I will come. 萬一我明天有時間，我就來。
此外，Why(or How) + should結構表示說話人對某事不能理解，感到意外、驚異等意思。意爲“竟會”。如：
⑧ Why should you be so late today? 你幾天怎麼來得這麼晚?
⑨ — Where is Betty living? — 貝蒂住在哪裏?
— How should I know? — 我怎麼會知道呢?
⑩ I don't know why you should think that I did it. 我真不知道你憑什麼認爲這件事是我乾的。
5. “should + have + 過去分詞”結構一般表示義務，表示應該做到而實際上沒有做到，幷包含一種埋怨、責備的口氣。如：
She should have finished it.
I should have helped her, but I never could.
You should have started earlier.
6) will和would的用法
1. 表示請求、建議等，would比will委婉客氣。如：
Would you pass me the book?
2. 表示意志、願望和決心。如：
I will never do that again.
They asked if we would do that again.
3. 用“will be”和“will(would) + have + 過去分詞”的結構表示推測，主要用於第二、三人稱。前者表示對目前情況的推測，後者表示對已經完成的動作或事態的推測。如：
This will be the book you want.
He will have arrived by now.
The guests would have arrived by that time.
I thought you would have finished this by now.
4. Would可表示過去反覆發生的動作或某中傾向。Would表過去習慣時比used to正式，並沒有“現已無此習慣”的含義。如：
The wound would not heal8.
During the vacation he would visit me every week.
5. 表料想或猜想。如：
It would be about ten when he left home.
What would she be doing there?
I thought he would have told you all about it.
7) ought to的用法
1. Ought to表示應該。如：
You ought to take care of him.
2. 表示推測。注意與must表示推測時的區別：
He must be at home by now. (斷定他已到家)
He ought to be home by now. (不十分肯定)
This is where the oil must be. (比較直率)
This is where the oil ought to be. (比較含蓄)
3. “ought to + have + 過去分詞”表示過去應做某事而實際未做。如：
You ought to have asked him (but you didn't).
這時，ought to和should可以互相換用。
注意：在美國英語中，ought to用於否定句和疑問句時，to可以省略。如：
Ought you smoke so much?
You oughtn't smoke so much.
8) used to，had better，would rather的用法
1. Used to表示過去的習慣動作或狀態，現在已不存在，在間接引語中，其形式可不變。如：
He told us he used to play football when he was young.
在疑問句、否定句、否定疑問句或強調句中，可有兩種形式：
疑問句
Did you use to go to the same school as your brother?
Used you to go to the same school as your brother?
否定句
I usedn't to go there.
I didn't use to go there.
Usedn't 亦可拼作usen't，但發音皆爲[ju:znt]。
否定疑問句
Usen't you to be interested in the theatre?
Didn't you use to be interested in the theatre?
強調句
I certainly used to smoke, but it was a long time ago.
I certainly did use to smoke, but it was a long time ago.
其反意疑問句或簡略回答中，也有兩種形式：
She used to be very fat, didn't she? (正式)/ use(d)n't she? (口語)
Did you use to play chess? Yes, I did.
Used you to get up early in the morning? Yes, I did. (Yes, I used to.)
2. Had better意爲“最好”，後接不帶to的不定式。如：
— We had better go now.
— Yes, we had (we'd better / we had better).
Hadn't we better stop now? (Had we better not stop now?)
I think I'd better be going. (用於進行時態，表“最好立即”)
You had better have done that. (用於完成時態，表未完成動作)
注：①had best與had better同意，但較少用。②You had better … 用於同輩或小輩，對長輩不可用。
3. Would rather意爲“寧願”，表選擇，後接不帶to的不定式。如：
I'd rather not say anything.
Would you rather work on a farm?
— Wouldn't you rather stay here?
— No, I would not. I'd rather go there.
由於would rather表選擇，因而後可接than。如：
I would rather work on a farm than in a factory.
I would rather watch TV than go to see the film.
I would rather lose a dozen cherry trees than that you should tell me one lie.
I'd rather you didn't talk about this to anyone. (句中的'd rather不是情態動詞，would在此是表願望的實義動詞)
命題熱點：
情態動詞的命題熱點有： 情態動詞基本用法辨析，情態動詞表示態度的用法辨析，情態動詞表示推測的用法辨析，情態動詞在虛擬語氣中的運用。
考查情態動詞的基本用法
一些常見情態動詞的非常用意義往往爲高考考查的焦點，考生須確切理解其含義並根據句子意思選擇正確的情態動詞。
考查情態動詞的推測用法
1、對現在或客觀事實的推測
對現在或客觀事實的肯定推測一般用must，will，should，may(might)或could，語氣依次遞減。
2、對過去事實的推測
對過去已發生事情的肯定推測常用“must/may/might+have+v-ed”，“must+have+v-ed”意思爲“想必、準是、一定是”，語氣非常肯定且只能用於肯定句，“may/might+have+v-ed”意思爲“也許、或許”表示推測的把握不大，只能用於肯定或否定句，不用於疑問句;對過去的否定推測常用“can/could/may’might not+have+v-ed”，意思爲“不可能/可能沒做過……”;對過去的疑問推測只用“can/could+have+v-ed”，意思爲“可能已經……”。
另外，考查情態動詞的虛擬用法的題目考生也要重點複習。
備考建議
掌握情態動詞的基本詞義及其用法是把握情態動詞的關鍵，同時要認真比較每個情態動詞的用法，注意其細微差別，如shall，can，must，should，will的用法差異;熟悉每個情態動詞的適用場合，根據語境及說話人的語氣選擇恰當的情態動詞，如用於推測時，must只用於肯定句中，can一般不能用於肯定句中。may/might不能用於疑問句中;牢記情態動詞表示推測的用法，尤其是對過去發生情況的推測;積累虛擬語氣的用法，尤其是一些句式和特殊情況。
