情態(tài)動(dòng)詞的概念:
情態(tài)動(dòng)詞表示說話人對(duì)某一動(dòng)作或狀態(tài)的態(tài)度。
幾組詞的辨析:
1、need和dare的用法:
need和dare既可用作情態(tài)動(dòng)詞,也可用作實(shí)義動(dòng)詞。用作情態(tài)動(dòng)詞時(shí),主要用于否定句和疑問句。用作實(shí)義動(dòng)詞時(shí),可用于各種句式。
(1)用作情態(tài)動(dòng)詞:
如:—Need I come? 我需要來嗎?
—Yes, you must. 需要。
You needn′t telephone him now. 你現(xiàn)在不必打電話給他。
I don′t think you need worry. 我想你不必發(fā)愁。
She dare not go out alone at night. 她晚上不敢一個(gè)人出去。
How dare you say I′m unfair? 你竟敢說我不公平?
Not one of them dared mention this.他們誰也不敢提這件事。
。2)用作實(shí)義動(dòng)詞:
如:You don′t need to do it yourself. 你不必親自做這件事。
We need to tell them the news. 我們需要把這消息告訴他們。
The table needs painting(to be painted.). 桌子需要油漆一下。
We should dare to give our own opinion.我們要敢于提出自己的觀點(diǎn)。
He did not dare(to) look up. 他不敢抬頭看。
I dare day he′ll come again. 我想他會(huì)再來的。
2、can和be able to:
。1)情態(tài)動(dòng)詞can只有兩種時(shí)態(tài)形式,現(xiàn)在式can和過去式could,而be able to有多種時(shí)態(tài)形式。
如:Mary can play the piano. She has been able to play it since she was 5. 瑪麗會(huì)彈鋼琴。她五歲起就會(huì)彈了。
(2)用在過去時(shí)中,could經(jīng)常表示能夠做某事,事實(shí)上不一定去做,而was∕were able to則表示“過去做成了某事”。在否定句中兩者可通用。
如:He could swim across the English Channel. But he didn′t feel like it that day.
他能游過英吉利海峽,但那天他不想游。
Yesterday I was able to get home before the heavy rain. 昨天我在下大雨前趕到了家里。
3、must和have to:
must表示主觀意志,而have to表示由于客觀因素不得不做某事。must沒有過去式,除在間接引語中可用于表示過去時(shí)間,在直接引語中表示過去時(shí)間應(yīng)該用had to代替。
如:I told her that she must give up smoking. 我叫她必須戒煙。
We had to get everything ready that night. 我們那晚得把一切準(zhǔn)備就緒。
4、would和used to:
(1)usedto表示過去與現(xiàn)在或過去某時(shí)與后來的情況有不同,而would只表過去的情況。
如:People used to think that the earth was flat. 過去人們認(rèn)為地球是平的。(現(xiàn)在人們不這么認(rèn)為。)
She would go out for a walk in the morning when she was in the country.
在鄉(xiāng)下時(shí),她總是在早晨去散會(huì)兒步。(可能現(xiàn)在仍有散步的習(xí)慣。)
(2)used to可表示過去的習(xí)慣動(dòng)作和經(jīng)常的情況,而would只表示過去的習(xí)慣動(dòng)作。
如:He used to∕would smoke while writing. 過去他寫東西時(shí)常抽煙。
She used to be fat. 她過去很胖。
情態(tài)動(dòng)詞的基本用法:
1、can(could):
1)表示能力,could主要指過去時(shí)間。
如:Two eyes can see more than one. 兩只眼比一只眼看得清。
Could the girl read before she went to school? 這女孩上學(xué)前能識(shí)字嗎?
2)表示可能(理論上或是邏輯判斷上)。
如:The temperature can fall to–60℃, that is 60℃ below freezing. 氣溫可降至-60℃,也就是零下60℃。
He can′t(couldn′t) have enough money for a new car. 他不可能有足夠的錢買新車。
You mustn′t smoke while you′re walking around in the wood. You could start a fire.
在林子里走時(shí)勿吸煙,那樣可能會(huì)引起火災(zāi)。
3)表示允許。
如:Can I have a look at your new pen? 我可以看一看你的新鋼筆嗎?
He asked whether he could take the book out of the reading-room. 他問他可不可以把書帶出閱覽室。
4)表驚異、懷疑、不相信等態(tài)度。主要用于否定句、疑問句或感嘆句中。
如:Where can(could) they have gone to? 他們會(huì)去哪兒了呢?
He can′t(couldn′t) be over sixty. 他不可能超過六十歲。
How can you be so careless? 你怎么這么粗心?
5)比較委婉客氣地提出問題或陳述看法。
如:Can(Could) you lend me a hand? 幫我一把好嗎?
I′m afraid we couldn′t give you an answer today. 恐怕我們今天不能給你答復(fù)。
2、may(might):
1)表允許,might可以指過去時(shí)間,也可指現(xiàn)在時(shí)間,語氣更委婉。
如:You may take what ever you like. 你喜歡什么就拿什么。
He told me that I might smoke in the room. 他告訴我可以在房間里抽煙。
May(Might) I ask for a photo of your baby? 我可以要一張你寶寶的照片嗎?
在回答以may引起的問句時(shí),多避免用這個(gè)詞,而用其它方式:
如:Yes, please./Certainly. /Please don′t./You′d better not./No, you mustn′t.等,以免顯得太嚴(yán)峻或不客氣。
2)表可能(事實(shí)上)?梢灾高^去時(shí)間,也可以指現(xiàn)在時(shí)間,但語氣更加不肯定。
如:He may be at home. 他可能在家。
She may not know about it. 她可能不知道這件事。
He was afraid they might not agree with him. 他擔(dān)心他們可能不同意他的意見。
如:They might be having a meeting, but I′m not sure. 他們有可能在開會(huì),不過我不肯定。
3、must:
1)表示義務(wù)。意為“必須”(主觀意志)。
如:We must do everything step by step. 我們一切都必須循序漸進(jìn)地做。
You mustn′t talk to her like that. 你不可能那樣對(duì)她說話。
—Must we hand in our exercise-books now? 我們現(xiàn)在就要交練習(xí)本嗎?
—No, you needn′t./No, you don′t have to.不必。(這種情況下,一般不用mustn′t)
2)表示揣測(cè)。意為“想必、準(zhǔn)是、一定”等,只用于肯定句。
如:He must be ill. He looks so pale. 他準(zhǔn)是病了。他的臉色蒼白。
如:She′s wearing a diamond necklace. She must have a lot o fmoney. 她戴著鉆石項(xiàng)鏈,一定很有錢。
4、shall:
1)表征詢意見,用于第一、第三人稱疑問句。
如:Shall I get you some tea? 我給你點(diǎn)茶好嗎?
Shall the boy wait outside? 讓那男孩在外面等嗎?
What shall we do this evening? 我們今晚做什么?
2)表說話人的意愿,有“命令、允諾、警告、決心”等意思,用于第二、第三人稱陳述句。
如:You shall do as I say. 按我說的做。(命令)
You shall have my answer tomorrow. 你明天可以得到我的答復(fù)。(允諾)
He shall be sorry for it one day, I tell you.有一天他會(huì)后悔的,我告訴你。(警告)
如:Nothing shall stop us from carrying out the plan.什么也不能阻止我們執(zhí)行這項(xiàng)計(jì)劃。(決心)
5、will:
1)表意愿,用于各種人稱陳述句。
如:I will do anything for you. 我愿為你做任何事。
None is so blind as those who won′t see. 不愿看的人眼最瞎。
If you will read the book, I′ll lend it to you. 如果你愿意讀這本書,我會(huì)把它借給你。
2)表請(qǐng)求,用于疑問句。
如:Will you close the window? It′s a bit cold. 請(qǐng)你把窗戶關(guān)上好嗎?有點(diǎn)冷。
Won′t you drink some more coffee? 再來一點(diǎn)咖啡好嗎?
3)表示某種傾向或習(xí)慣性動(dòng)作。
如:Fish will die out of water. 魚離開水就不能活。
The door won′t open. 這門打不開。
The boy will sit there hour after hour looking at the traffic go by.
那男孩常常坐在那里好幾個(gè)鐘點(diǎn),看著車輛行人通過。
6、should:
1)表義務(wù)。意為“應(yīng)該”(某件事宜于做),用于各種人稱。
如:You should be polite to your teachers. 你對(duì)老師應(yīng)該有禮貌。
You shouldn′t waste anytime. 你不應(yīng)該浪費(fèi)時(shí)間。
2)表推測(cè),意為“想必一定、照說應(yīng)該、估計(jì)”等。
如:The film should be very good as it is starring first-class actors. 這部新電影是一流演員主演的,估計(jì)拍得很好。
They should be home by now. 照說他們現(xiàn)在應(yīng)當(dāng)已經(jīng)到家了。
7、would:
1)表意愿。
如:They would not let him in because he was poorly dressed. 他們不讓他進(jìn)去因?yàn)樗轮婆f。
I said I would do anything for you. 我說過我愿意為你做任何事。
2)表委婉地提出請(qǐng)求、建議或看法。
如:Would you like another glass of beer? 再來杯啤酒好嗎?
Would you mind cleaning the window? 請(qǐng)把窗戶擦一下好嗎?
They wouldn′t have anything against it. 他們不會(huì)有什么反對(duì)意見。
3)表過去反復(fù)發(fā)生的動(dòng)作或過去的一種傾向。
如:Every time she was in trouble, she would go to him for help. 她每遇到麻煩都會(huì)向她求助。
8、ought to:
1)表義務(wù),意為“應(yīng)該”(因責(zé)任、義務(wù)等該做),口氣比should稍重。
如:You are his father. You ought to take care of him. 你是他父親,應(yīng)當(dāng)管他。
You oughtn′t to smoke so much. 你不應(yīng)該抽這么多煙。
2)表推測(cè),暗含很大的可能,語氣較弱。
如:Han Mei ought to know his telephone number. 韓梅該知道他的電話號(hào)碼。
There′s a fine sun set; it ought to be a fine day tomorrow. 今天有晚霞,明天應(yīng)該是個(gè)好天。
9、used to:
表示過去的習(xí)慣動(dòng)作或狀態(tài),現(xiàn)在不復(fù)發(fā)生或存在。疑問式和否定式有兩種。
如:He used to live in the countryside, but now he lives in the city. 他過去住在鄉(xiāng)下,現(xiàn)在住在城里。
There used to be a building at the street corner, but it has been pulled down. 街道拐角處過去有座樓房,現(xiàn)在拆了。
I usedn′t (didn′t use) to smoke. 我過去不抽煙。
Used you(Did you use) to go to school on foot? 你過去常步行去學(xué)校嗎?
情態(tài)動(dòng)詞的其他用法:
首先它是動(dòng)詞,而且不同于行為動(dòng)詞,行為動(dòng)詞表示的是可以通過行為來表達(dá)的動(dòng)作(如寫,讀,跑),而情態(tài)動(dòng)詞只是表達(dá)的一種想法(如能,也許,敢)。
用法是:情態(tài)動(dòng)詞+行為動(dòng)詞原形:
句:I can read this sentence in English. 我能用英語讀這句話。
情態(tài)動(dòng)詞是一種本身有一定的詞義,表示說話人的情緒,態(tài)度或語氣的動(dòng)詞,但不能單獨(dú)作謂語,只能和其他動(dòng)詞原形構(gòu)成謂語。
如:We can be there on time tomorrow. 我們明天能按時(shí)去那兒。
May I have your name? 我能知道你的名字嗎?
Shall we begin now? 我們現(xiàn)在就開始嗎?
You must obey the school rules. 你必須遵守校規(guī)。
情態(tài)動(dòng)詞知識(shí)體系:
情態(tài)動(dòng)詞表推測(cè)的三種句式:
1、在肯定句中一般用must(一定),may(可能),might/could(也許,或許)。
如:He must/may/might know the answer to this question? 他一定/可能/也許知道這個(gè)問題的答案。
It is cold in the room. They must have turned off the heating. 屋里很冷,他們肯定把暖氣關(guān)了。
2、否定句中用can't/couldn't (不可能), may not/might not(可能不)。
如:It can't/couldn't be the headmaster. He has gone to America. 這不可能是校長(zhǎng),他去美國(guó)了
He may not/might not know the scientist. 他也許不認(rèn)識(shí)那位科學(xué)家。
3、疑問句中用can/could(能……?)。
如:Could he have finished the task? 他可能把任務(wù)完成了嗎?
Can he be at home now? 他現(xiàn)在能在家嗎?
注:以上三種句式中情態(tài)動(dòng)詞的語氣按程度都是依次遞減的。Might, could并非may, can的過去式,而表示語氣較為委婉或可能性較小。
情態(tài)動(dòng)詞表推測(cè)的三種時(shí)態(tài):
1、對(duì)將來情況的推測(cè),用“情態(tài)動(dòng)詞+動(dòng)詞原形”。
如:She must/may/might/could arrive before 5. 5:00前她一定/可能/也許到。
She must/may/might/could walk miles and miles among the hills without meeting anyone.
她一定/可能/也許會(huì)在山里一連走好幾英里而遇不到一個(gè)人。
2、對(duì)現(xiàn)在或一般情況的推測(cè),用“情態(tài)動(dòng)詞+be”,“情態(tài)動(dòng)詞+bedoing”或“情態(tài)動(dòng)詞+動(dòng)詞原形”。
如:He must/may/might/could be listening to the radio now. 他一定/可能/也許正在聽收音機(jī)。
He can't(couldn't)/may(might) not be at home at this time. 這個(gè)時(shí)候他不可能/可能不在家。
Mr. Bush is on time for everything. How can(could) he be late for the opening ceremony?
布什先生一向準(zhǔn)時(shí),這次開幕式他怎么可能遲到呢?
3、對(duì)過去情況的推測(cè),用“情態(tài)動(dòng)詞+have+過去分詞”。
如:It must/may/might/ could have rained last night. The ground is wet. 地濕了,昨晚肯定/可能/也許下雨了。
The door was locked. He can(could) not/may(might) not have been at home. 門鎖著,他不可能/可能不在家。
Can/Could he have gotten the book?難道他找到書了嗎?
注:情態(tài)動(dòng)詞should/ought to表推測(cè)時(shí),意為“想必會(huì),理應(yīng)……”但與“have+過去分詞”連用時(shí),則又可構(gòu)成虛擬語氣意為“本應(yīng)該做某事卻沒做”。
如:It's seven o'clock. Jack should/ought to be here at any moment.
現(xiàn)在七點(diǎn)鐘了,杰克理應(yīng)隨時(shí)到達(dá)。(推測(cè))
She should/ought to have attended your birthday party, but she had to look after her mother in hospital.(虛擬)
她本該出席你的生日晚會(huì)的,可是她得在醫(yī)院照顧她媽媽。
Tom should not/ought not to have told me your secret, but he meant no harm.(虛擬)
湯姆本不該告訴我你的秘密,可是他并無惡意。