A. 高中英語情態動詞
①只做情態動詞:must,can,may……
②可做情態動詞又可做實義動詞：如：need,
dare
③具有情態動內詞特容征：have(had,has)
to,used
to,
ought
to
④可做情態動詞又可作助動詞：如：shall(should),will(would)[
注意
mustn't代表強烈禁止
must表示主觀，have
to表示客觀。
美式英語中常用must
not
而不用
mustn't.
mayn't,mightn't和shan't也很少用
常用
can
(could),
may
(might),
must,
need,
ought
to,
dare
(dared),
shall
(should),
will
(would)
B. 高中語法情態動詞
情態動詞表推測
1 如果是疑問或者否定的話 語氣最強烈的用法用Can。（我記得表示否版定的話也權可以用might的，但是這是特殊情況。一般大多用Can 或者could）
2 表示肯定的話 語氣最強為must 還可以用may might不過只是語氣強烈程度不同must語氣最強接著是may下來是might
不能繼續說了 再說我想LZ就暈了
C. 高中英語語法里的一個情態動詞的一個題目
這句話首先說 你能彈奏很多樂器（Since you can play many musical instruments） 後面 有兩個詞要注意 一個是called 這里做認為。 第二版個是 accoomplishment 成就 還有一權個 well be 表被動
現在分別把這兩個詞帶入句子 第一個是 必須被認為一個人的成就 而二個是可能被認為一個人的成就。 作為認為的主題 成就是不能被必須認為的。 不是帶強制性的 所以 這里用may而不能用must
D. 高中英語語法：情態動詞
情態動詞有四類：
①只做情態動詞：must,can(could),may(might)……
②可做情態內動詞又可做實義動詞：容need,dare
③具有情態動詞特徵：have(had,has)
to,used
to
④情態動詞表猜測
E. 高中英語語法情態動詞
shall 用在二三人稱的陳述句中表 命令，威脅，允諾，警告 的語氣You shall not leave your post . （表命令）回 問題中的答這句也是表命令的語氣
用於一，三人稱的疑問句表徵求意見 Shall he go home now? Shall we go out for a walk?
F. 高中英語情態動詞的用法有哪些
情態動詞的考點精簡
一、何謂「情態動詞」？
情態動詞主要用來表示說話人的情感、態度等，是中學英語語法的重點，也是高考的熱點，是單項填空必考的一個知識點。高考試題常常藉助語境和句子之間意義上的細微差別來考查學生對情態動詞的基本用法及其區別，近五年高考中主要考查四點：情態動詞表示推測和可能性的用法；情態動詞與虛擬語氣；情態動詞的表達「情感、態度、語氣等」，情態動詞表示 「必要性」等方面的用法。
二、情態動詞的特點
1.沒有人稱和數的變化。
2. 有些情態動詞有過去式的變化:
e.g. will → would , can → could , may→ might , dare → dared
三、情態動詞的否定形式
情態動詞+ not +動詞原形can not: can't , must not: mustn't , need not : needn't
四、情態動詞的用法（常考考點）
Shall
一）用於一、三人稱疑問句中，表示說話人徵求對方意見和向對方請示。
Shall we begin our class? Shall he come in, sir? (徵求對方意見)
二）用於二、三人稱 表命令、許諾、警告、規定、威脅、決心、也用於宣布法律、規定的要求
1. You shall get my reply tomorrow. (許諾)
2. 「The interest shall be divided into five parts, according to the agreement made by both side. （命令）
3. You shall be sorry for what you said one day, I tell you. (警告、威脅)
4. Nothing shall stop us from advancing. (決心)
5. —What does the sign over there read?
—「No person shall smoke or carry a lighted cigarette，cigar or pipe in this area.」(要求)
Should
一）應該，表示責任、義務
According to the air traffic rules, you should switch off your mobile phone before boarding.
二）竟然、（ 從句中） 驚奇、懷疑、不滿(expect\, think, believe等詞後） 委婉 客氣（第一人稱 ） 驚訝、埋怨 （二、三人稱） 萬一（ if 從句中）
1.） it』s a pity that he should be so careless. (竟然)
2.） I never expect that you should have come here. (驚奇 )
3.） I should advise you not to do it. (委婉 客氣)
4.） Who should come to see you when you are in trouble! (埋怨 )
5.）If you should change your mind, please let me know. (萬一)
三） 表示合理的推測
The video should be very interesting, in which you can see foreigners making Jiaozi ring the Spring Festival.
四）if 引導的虛擬條件句中，從句中只可出現should.
Should I have time, I would go there with you.
五）要求，命令和請求含義的動詞後，接賓語從句，從句中謂語「should do」,should 可以省略
Tom suggested that I (should) go there at once.
六）should have done 本應該做但是沒做
shouldn』t have done 本不應該做但是做了
You should have studied hard.
Must
一）表示必須要做的事: 必須
-Must I get to the station before three o'clock?
-Yes, you must. ( No, you needn't. )
二）用於指 偏要、硬要 （ 令人不快的事）
1. The car must break down just when we were in the jungle. (偏要)
2. -- Could I have a word with you, mum?
-- Oh, dear, if you must.
3. – Who is the girl standing over there?
-- Well, if you must know, her name is Mabel.
三）用於表肯定的猜測
He is absent today, and something must have happened to him.
She must be at home now, as I just called her.
四）禁止 (否定句)
You mustn』t make noises in the library. (禁止) (註：mustn』t沒有表推測的意思)
Can\ could
一） 能力（陳述句）He can swim./ He could swim when he was a child.
二） 驚異、懷疑、不相信（否定、疑問、驚嘆句）How can you be so careless？
三） can』t 表推測「一定不是」 He can』t be Mr. White, because I don』t know him.
四） can/ could 用於否定和疑問表猜測 I lost my purse. Where could I have put it?
五） can 用於客觀事實的推測，可能出現的某種現象
He is friendly, but sometimes he can be difficult to get along with.
The northern part of China is cold, but sometimes it can be warm.
Nowadays, graates can have difficulty finding jobs.
六） be able to do sth. 經過努力能達到
4. The fire in the hotel spread fast but fortunately all of the people were able to ran out. (經過努力能達到)
May \ might
一）祝願（祈使句） May you return in safety. (祝願)
二）可以（語氣弱）. May I come in ? (可以)
三）表推測，不太可能的推測 Helen may go on the trip with us, but she isn』t quite sure yet.
四）may as well do sth. Now that you are here, you may as well try your best.
may well do sth. He may not well go with us—he hates travel.
五）might用於虛擬 If he came here tomorrow, he might have a chance of talking with her.
Will
一）意願、決心、習慣性、傾向性、請求
1. I』ll do my best . (意願)
2. I will never do such a thing again. (決心)
3. Fish will die without water. (習慣性、傾向性)
4. Will you give me a piece of paper? (請求)
二）區分於be going to, 表示沒有計劃，臨時決定
---I』m sorry. I forgot to send the letter for you.
--- It doesn』t matter. I will go myself.
Would He promised he would never smoke again. (will的過去式)
Would you…? 「I would like to… (婉轉語氣)
Last year our English teacher would sometimes tell us stories in English after class.
(過去的習慣動作,比used to正式，並沒有「現已無此習慣」的含義。)
It would be about ten when he left home. (表料想或猜想)
Dare \ need
1. I dare to go there alone at night.
2. Do you dare to go there alone at night? = Dare you go there alone at night?
3. I don』t dare (to )go there alone at night. = I dare not go there alone at night.
dare say\ dare tell \ dare speak
4 needn』t have done 本沒有必要做，但是做了
You needn』t have waited for her, as she didn』t go there.
情態動詞+ do 表示對現在的推測
情態動詞+ have done 表示對過去的推測（對過去的一種結果的假設或虛擬）
(1) should (not) / ought (not) to have done本（不）應該做某事，但卻沒有做或做了，含有責備或後悔之意。
例如： —I』m sorry. I _________at you the other day. B
—Forget it. I was a bit out of control myself.
A. shouldn』t shout B. shouldn』t have shouted
C. mustn』t shout C. mustn』t have shouted
(2) could have done本來能夠做某事但未做。例如：
Thank you for all your hard work last week. I don』t think we ______ it without you. B
A. can manage B. could have managed
C. could manage D. can have managed
(3) needn』t have done本沒有必要做某事但卻做了。要注意needn』t do則表達「沒有必要去做某事」，時間上應該是現在或將來。例如：
—Catherine, I have cleaned the room for you. B
—Thanks. You ________ it. I could manage it myself.
A. needn』t do B. needn』t have done
C. mustn』t do D. shouldn』t have done
(4)would (not) have done本來(不)會發生某事，但卻（發生了）或沒有發生。常用於虛擬條件句或含蓄虛擬條件引導的虛擬語氣，表示對過去所發生事情結果的假設。例如：
He hesitated for a moment before kicking the ball, otherwise, he ________ a goal. D
A. had scored B. scored
C. would score D. would have scored
(5) might have done表示「本來可能……」，但實際上沒有發生的事。例如：
What a pity! Considering his ability and experience, he ________ better. D
A. need have done B. must have done
G. 高中英語常見的情態動詞且它們的意思
情態動詞
★基本概念和用法：
情態動詞是一類本身具有一定詞義的動詞，但沒有人稱和數的變化，也不能單獨使用，它必須要和其他動詞連用作句子的謂語。情態動詞可表示語氣、建議、要求、可能和意願等。常用的情態動詞有：can, could, may, might, must, shall, should, will, would, ought to, need, dare等。
★情態動詞的基本用法
1. can (could) 表能力、允許、(從理論上或邏輯上判斷）可能性以及表驚異、懷疑、不相信等態度（主要用於否定句、疑問句或感嘆句中）。could指過去或表示語氣委婉。例如：
The boy can speak three languages.這個孩子能說三種語言.
Can I borrow the book from the library?我能從圖書館里借書嗎？
I could swim when I was eight.我八歲的時候就能游泳。
2. may (might) 表允許、可能性、祝願等。might可以指過去，也可指現在，語氣更委婉。例如：
May (Might) I ask for a photo of your baby?我可以要一張你孩子的照片嗎？
She may be still waiting for us.她也許還在等我們呢。
May you have a happy holiday!祝你假期愉快！
3. will (would) 表意願(用於各種人稱的陳述句)、請求(用於疑問句)、某種傾向或習慣性動作等。would指過去或表示語氣委婉。例如：
Will you come this way, please?請這邊來。
Would you please close the window?請你關好窗子好嗎？
Fish will die without water.魚離開水會死。
Every time she was in trouble, she would go to him for help.每當她遇到麻煩，她都會找他幫忙。
4. must 表命令、推測（現在、過去或將來的猜測）、偏偏等含義。例如：
We must do everything step by step.你必須按部就班的做事情。
He must be ill. He looks so pale.他一定是病了，臉色看起啦這么蒼白。
It can』t help. He must go with me.這不管用，他必須跟我走。
5. shall 用於第一、三人稱疑問句中表示請求或徵求對方意見; 用於第二、三人稱陳述句中表示允諾、命令、警告、威脅、決心等。例如：
Shall I get you a cup of coffee?要我給你杯咖啡嗎？
You shall have my answer tomorrow.明天你就能得到我的答復。
He shall be sorry for it one day, I tell you.我告訴你，他總有一天會為此後悔。
6. should / ought to 表義務（因責任、義務等該做）、推測、建議等。ought to 的口氣比should稍重。例如：
You should be polite to your teachers.你應該對老師有禮貌。
You are his father so you ought to take care of him.你是他的父親，因此你應該照顧他。
★情態動詞的回答
疑問式
肯定回答
否定回答
Could I…?
Yes, you can.
Yes, go ahead.
No, you can』t.
Must I…?
Yes, you must.
No, you needn』t / don』t have to.
May I …?
Yes, of course.
Yes, please.
Yes, go ahead.
No, you mustn』t.
No, you can』t.
Will you ...?
Would you…?
Certainly. / Sure. / All right.
I』m sorry. I can』t.
No, thank you.
No, I won』t.
★辨析
1. can (could) 與be able to
can表示「能力」時，和be able to相當，許多場合都可以互換。但當敘述過去經過一番努力才能完成的事情或前面有特殊說明時，只能用be able to，且be able to可以用於各種時態。例如：
I can / am able to stand on my head.我能倒立。
I』m sorry I haven』t been able to answer your letter in time.非常抱歉我沒有能夠及時回答你的問題。
2. must與have to
must與have to都含有「必須」之意，must含有說話者的強烈決心 (表示主觀的看法)，have to則表示外部因素或習慣使然 (即表示客觀的必要，作「不得不」解)，且have to 有更多的時態形式。例如：
He said that he must work hard. （主觀） 他說他必須努力學習。
My brother was very ill, so I had to call the doctor in the middle of the night. (客觀) 媽媽病了，因此我不得不在半夜裡叫醫生。
We』ll have to help them as much as we can.我們將不得不盡力幫助他們。
3. would 與used to
would表示過去的習慣性動作時，只表示過去的情況，與現在無關，往往要帶有一個特定的時間狀語；used to可表示過去的習慣動作或狀態，強調「現在已無此習慣」。例如：
Whenever we were in the country, we would play hide-and-seek in the fields. 無論什麼時候我們在鄉下，我們都會玩捉迷藏。
We used to play hide-and-seek in the fields.我們過去常在野外玩捉迷藏。
★ 情態動詞+ have +過去分詞
1) may(might) have + done sth, can (could) have + done sth.表示過去，推測過去時間里可能發生的事情。
Philip may (might) have been hurt seriously in the car accident. 菲利普也許在車禍中嚴重受傷的。
2)must have +done sth.，對過去時間里可能發生的事情的推測，語氣較強，具有「肯定」的意思。
--- Linda has gone to work, but her bicycle is still here.琳達已經去工作了，但是她的自行車還在這里。
---She must have gone by bus.她一定是坐公車去的。
3) ought to have done sth., should have done sth. 本應該做某事，而事實上並沒有做。否定句表示"不該做某事而做了"。
You ought to (should) have been more careful in this experiment.你在實驗中本該更認真一點的。
He ought not to have thrown the old clothes away.你本不該舊衣服扔掉的。（事實上已扔了。）
注意：ought to 在語氣上比should 要強。
4) needn』t have done sth 本沒必要做某事
I dressed very warmly for the trip, but I needn』t have done so. The weather was hot.我穿的很暖和去度假，但是我沒有必要這樣穿，天氣太熱了。
H. 高中英語，情態動詞
1. If The price of the goods _____ continue going up ,the socity would face a more difficult situation.
該題是對將來的條件虛擬，在條件從句中表示對將來的虛擬，謂語動詞可以用三種形式表示：
1）動詞的過去形式（動詞 be 一般用 were 表示），如：
If The price of the goods continued going up ,the socity would face a more difficult situation. 假如貨價真的在事實上有上漲的可能，...
2) were to + 動詞原形，如：
If The price of the goods were to continue going up ,the socity would face a more difficult situation. 假如貨價真的有上漲的計劃，...
3）should + 動詞原形, 如本題的選擇：
If The price of the goods should continue going up ,the socity would face a more difficult situation.假如貨價將來真的有可能上漲，...
注意：第三種一定是 should，這一點最容易與主句中的虛擬混淆。所以出現這種現象是由於條件虛擬從句的主句的謂語動詞根據意思需要可以選擇 should，would，might，could 或 ought to 加動詞原形，所以常被初學者誤以為條件句中也可以這樣用。
2. ____ fired ,your health care and other benefit will not be immediately cut off.
該題與上一題一樣，同樣是條件虛擬句，所不同的是本題是省去連詞 if 以後的倒裝，恢復回 if 連接以後就會一目瞭然：
If you should be fired, your health care and other benefit will not be immediately cut off.
3. "The property ____ be divided into five farts ,according to the testament will made by Mr white" declared the judge.
本題是對情態動詞的考查，區別如下：
A may ：用於表示可能性（也許）或者得到的允諾（允許）
B should 表示推測/推論（該是）或者是說話者的意願「應該」
C must 表示推斷或指具有較大的可能性（諒必/必定/肯定）或者義務（必須/應當）
D shall 用於陳述句第二、三人稱, 表示說話者的意圖、警告、命令、決心等, 主語的行動受講話者支配。
題目中 The property shall be divided into five parts ...的主語是第三人稱 property （財產），是由 judge （法官）宣布的判決。
I. 高中英語，關於情態動詞使用
. 情態動詞
.1 情態動詞的語法特徵
1） 情態動詞不能表示正在發生或已經發生的事情，只表示期待或估計某事的發生。
2） 情態動詞 除ought 和have 外，後面只能接不帶to 的不定式。
3） 情態動詞沒有人稱，數的變化，即情態動詞第三人稱單數不加-s。
4） 情態動詞沒有非謂語形式，即沒有不定式，分詞，等形式。
.2 比較can 和be able to
1）cancould 表示能力；可能 (過去時用could),
只用於現在式和過去式(could)。be able to可以用於各種時態。
They will be able to tell you the news soon. 他很快就能告訴你消息了。
2）只用be able to
a. 位於助動詞後。
b. 情態動詞後。
c. 表示過去某時刻動作時。
d. 用於句首表示條件。
e. 表示成功地做了某事時，只能用was/were able to， 不能用could。
He was able to flee Europe before the war broke out.
= He managed to flee Europe before the war broke out.
注意：could不表示時態
1）提出委婉的請求，（注意在回答中不可用could）。
--- Could I have the television on?
--- Yes, you can. / No, you can't.
2）在否定，疑問句中表示推測或懷疑。
He couldn't be a bad man.
他不大可能是壞人。
.3 比較may和might
1） 表示允許或請求；表示沒有把握的推測；may 放在句首，表示祝願。
May God bless you!
He might be at home.
注意： might 表示推測時，不表示時態。只是可能性比may 小。
2） 成語： may/might as well，後面接不帶to 的不定式，意為"不妨"。
If that is the case, we may as well try.
典型例題
Peter ___come with us tonight, but he isn't very sure yet.
A. mustB. may C. can D. will
答案B. 表可能性只能用may.此句意可從後半句推出。
.4 比較have to和must
1)兩詞都是'必須'的意思，have to 表示客觀的需要， must 表示說話人主觀上的看法，既主觀上的必要。
My brother was very ill, so I had to call the doctor in the middle of the night.我弟弟病得很厲害，我只得半夜裡把醫生請來。(客觀上需要做這件事)
He said that they must work hard. 他說他們必須努力工作。（主觀上要做這件事）
2)have to有人稱、數、時態的變化，而must只有一種形式。但must 可用於間接引語中表示過去的必要或義務。
He had to look after his sister yesterday.
3） 在否定結構中： don't have to 表示"不必"
mustn't表示"禁止"，
You don't have to tell him about it. 你不一定要把此事告訴他。
You mustn't tell him about it.你一定不要把這件事告訴他。
.5 must表示推測
1) must用在肯定句中表示較有把握的推測，意為"一定"。
2) must表對現在的狀態或現在正發生的事情的推測時， must 後面通常接系動詞be 的原形或行為動詞的進行式。
You have worked hard all day.You must be tired. 你辛苦幹一整天，一定累了。（對現在情況的推測判斷）
He must be working in his office. 他一定在辦公室工作呢。
比較：
He must be staying there.
他現在肯定呆在那裡。
He must stay there.
他必須呆在那。
3) must 表示對已發生的事情的推測時，must 要接完成式。
I didn't hear the phone. I must have been asleep.我剛才沒有聽到電話，我想必是睡著了。
4) must表示對過去某時正發生的事情的推測，must 後面要接不定式的完成進行式。
---Why didn't you answer my phone call?
---Well, I must have been sleeping, so I didn't hear it.
5) 否定推測用can't。
If Tom didn't leave here until five o'clock, he can't be home yet.如果湯姆五點才離開這兒，他此時一定還未到家。
.6 表示推測的用法
can, could, may, might, must 皆可表示推測，其用法如下：
1）情態動詞+動詞原形。
表示對現在或將來的情況的推測，此時動詞通常為系動詞。
I don't know where she is, she may be in Wuhan.
2）情態動詞+動詞現在進行時。
表示對現在或將來正在進行的情況進行推測。
At this moment, our teacher must be correcting our exam papers.
這時，我們老師想必在批改試卷。
3）情態動詞+動詞完成時。
表示對過去情況的推測。
We would have finished this work by the end of next December.
明年十二月底前我們很可能已完成這項工作了。
The road is wet. It must have rained last night.
地是濕的，昨天晚上一定下雨了。
4）情態動詞+動詞的現在完成進行時。
表示對過去正在發生事情的推測。
Your mother must have been looking for you.
你媽媽一定一直在找你。
5）推測的否定形式，疑問形式用can't, couldn't表示。
Mike can't have found his car, for he came to work by bus this morning.
邁克一定還沒有找回他的車，因為早上他是坐公共汽車來上班的。
注意：could, might表示推測時不表示時態，其推測的程度不如can, may。
.7 情態動詞+ have +過去分詞
1) may(might) have + done sth, can (could) have + done sth表示過去，推測過去時間里可能發生的事情。
Philip may (might) have been hurt seriously in the car accident.
Philip can (could) have been hurt seriously in the car accident.
2)must have +done sth，對過去時間里可能發生的事情的推測，語氣較強，具有"肯定"，"諒必"的意思。
---Linda has gone to work, but her bicycle is still here.
---She must have gone by bus.
3) ought to have done sth, should have done sth
本應該做某事，而事實上並沒有做。否定句表示"不該做某事而做了"。
You ought to (should) have been more careful in this experiment.
He ought not to have thrown the old clothes away.（事實上已扔了。）
ought to 在語氣上比should 要強。
4) needn't have done sth 本沒必要做某事
I dressed very warmly for the trip, but Ineedn't have done so. The weather was hot.
5) would like to have done sth 本打算做某事
I would like to have read the article, but I was very busy then.
.8 should 和ought to
should 和ought to 都為"應該"的意思，可用於各種人稱。
---Ought he to go?
---Yes. I think he ought to.
表示要求，命令時，語氣由 should（應該）、had better最好）、must（必須）漸強。
.9 had better表示"最好"
had better 相當於一個助動詞，它只有一種形式，它後面要跟動詞原形。
had better do sth
had better not do sth
It is pretty cold. You'd better put on my coat.
She'd better not play with the dog.
had better have done sth表示與事實相反的結果，意為"本來最好"。
You had better have come earlier.
.10 would rather表示"寧願"
would rather do
would rather not do
would rather… than… 寧願……而不願。
還有would sooner, had rather, had sooner都表示"寧願"、"寧可"的意思。
If I have a choice, I had sooner not continue my studies at this school.
I would rather stay here than go home. = I would stay here rather than go home.
典型例題
----Shall we go skating or stay at home?
----Which ___ do?
A. do you ratherB. would you rather C. will you rather D. should you rather
答案B。本題考查情態動詞rather的用法，would rather +do sth 意為"寧願"，本題為疑問句，would 提前，所以選B。
.11 will和would
注意：
1）would like； Would like to do = want to 想要，為固定搭配。
Would you like to go with me?
2）Will you…?Would you like…? 表示肯定含義的請求勸說時，疑問句中一般用some, 而不是any。
Would you like some cake?
3）否定結構中用will，一般不用would, won't you是一種委婉語氣。
Won't you sit down?
.12 情態動詞的回答方式
問句肯定回答否定回答
Need you…?Yes, I must.No,I needn't
Must you…?/don't have to.
典型例題
1）---Could I borrow your dictionary?
---Yes, of course, you____.
A. mightB. will C. can D. should
答案C.could表示委婉的語氣，並不為時態。答語中of course，表示肯定的語氣，允許某人做某事時，用can和 may來表達，不能用could或might。復習： will 與you連用，用來提出要求或下命令。should與you 連用，用來提出勸告。
2）---Shall I tell John about it?
---No, you ___. I've told him already.
A. needn'tB. wouldn'tC. mustn'tD. shouldn't
答案A。needn't 不必，不用。 wouldn't 將不, 不會的。 mustn't 禁止、不能。 shouldn't不應該。本題為不需要，不必的意思，應用needn't。
3）---Don't forget to come to my birthday party tomorrow.
---______.
A. I don't B.I won't C. I can'tD. I haven't
答案B.will既可當作情態動詞，表請求、建議、也可作為實義動詞表"意願、意志、決心"，本題表示決心，選B。
.13 帶to 的情態動詞
帶to 的情態動詞有四個：ought to, have to, used to, be to, 如加上have got to ,(=must), be able to，為六個。它們的疑問，否定形式應予以注意：
Do they have to pay their bill before the end of the month?
She didn't use to play tennis before she was fourteen.
You ought not to have told her all about it.
Ought he to see a heart specialist at once.?
ought to 本身作為情態動詞使用。其他的詞作為實義動詞使用，變疑問，否定時，須有do 等助動詞協助。
典型例題
Tom ought not to ___ me your secret, but he meant no harm.
A.have toldB.tellC.be tellingD. having told
答案A。由於後句為過去時，告訴秘密的動作又發生在其前因，此地應用過去完成時，但它在情態動詞 ought to 後，所以用have。
.14 比較need和dare
這兩詞既可做實義動詞用，又可做情態動詞用。作為情態動詞，兩者都只能用於疑問句，否定句和條件句。 need 作實義動詞時後面的不定式必須帶to，而dare作實義動詞用時, 後面的to 時常可以被省略。
1) 實義動詞： need（需要, 要求）
need + n. / to do sth
2) 情態動詞： need，只用原形need後加do，否定形式為need not。
Need you go yet?
Yes, I must. / No, I needn't.
3) need 的被動含義：need, want, require, worth（形容詞）後面接doing也可以表示被動：
need doing = need to be done