1) 作情態(tài)動詞的用法:
a. 用于否定結(jié)構(gòu)中,表示“不必”
You needn't make two copies. One will do. 你不必寫兩份,一份就行。
They needn't send me a receipt. 他們不必寄我收條。
You needn't come to the meeting if you're too busy. 如果你太忙就不必來開會了。
We needn't have packed our thick clothes. The weather was really warm. 我們本來不需要帶厚衣服的。天氣確實很暖和。
She needn't have come in person—a letter would have been enough. 她其實不必親自來的,寫封信就夠了。
She need not have been punished so severely. 她本來不必受這么嚴厲的懲罰。
Δ 可用在賓語從句中,即使主語動詞是過去式,仍可用need:
He said (says) I needn't pay till the 31st. 他說我到31日才需要付款。
They said he needn't send a deposit. 他們說他無需寄定金來。
b. 用在帶有否定意思的句子中:
I need hardly tell you that the job is dangerous. 我用不著告訴你這工作是危險的。
I scarcely need say how much I enjoyed the holiday. 我簡直不用說我假期過得多愉快。
Nobody need be afraid of catching the disease. 誰都不必害怕染上這種疾病。
I don't believe you need worry. 我認為你不必憂慮。
I don't think you need take it too seriously. 我想你對此不必太較真。
c. 可構(gòu)成疑問句:
Need I tell Tom? 我需要告訴湯姆嗎?
Need he do it at once? 他有必要馬上這樣做嗎?
Need we come tomorrow?——No, you needn't (Yes, you must). 我們要來嗎? ——不必來(你們得來)。
Why need you go today? 你為什么今天就得走?
Need you have paid so much? 你需要支付那么多錢嗎?
也可用在表示疑問的從句中:
I asked him whether he need go. 我問他是否必須得去。
I wonder if I need bring my mosquito-net. 不知我是否需要帶上蚊帳。
I do not see why we need discuss it further. 我看不出我們還有什么談下去的必要。
2) 作及物動詞的用法:
作為及物動詞,need表示“需要”,后面可以跟:
a. 名詞或代詞:
All living things need water. 一切生物都需要水。
I need a new film for my camera. 我需要一個新(照相)膠卷。
Do you need any help? 你需要什么幫助嗎?
What we need is some proof. 我們需要的是證明。
Don't go—I may need you. 別走了,我可能會需要你。
b. 不定式:
I need to ask some advice. 我需要求教。
Do we need to buy tickets in advance? 我們需要預先購票嗎?
I need to get some sleep. 我需要睡一會兒。
All you need to do is (to) fill in this form. 你只需要填一下這張表。
The instruments needed to be sterilized. 這些器械需要消毒。
c. 動名詞:
His hair needed cutting. 他的頭發(fā)該理了。
This jumper needs washing (to be washed). 這件套衫需要洗了。
The garden doesn't need watering—it rained last night. 花園無需澆水,昨晚下雨了。
d. 復合賓語:
He needed his eyes tested. 他需要請人驗光。
I need my coat mended. 我的上衣需要補一補。
I need you over to help me with the children. 我需要你過來幫我照料孩子。
We need you to work for us. 我們需要你幫我們工作。
1) 作情態(tài)動詞的用法:
作情態(tài)動詞時,dare表示“敢…”,這時沒有人稱形式,但有過去式dared,主要用于:
a. 否定句(有時借助助動詞,這時不定式可帶to也可不帶to):
I daren't ask her to marry me. 我不敢求她嫁給我。
The government dared not increase taxes again this year. 今年政府不敢再加稅了。
They dared not move. 他們不敢動。
She dare not say what she thinks. 她不敢說出她的想法。
He doesn't dare (to) say anything. 他什么都不敢說。
They were so frightened that they didn't dare go into the room. 他們怕得不敢進屋。
They didn't dare (to) disobey. 他們不敢不服從。
Δ 也可用在帶有否定意思的句子中:
I daren't have done it yesterday, but I think I dare now. 昨天我沒敢這樣做,但我想今天我敢。
No one dared speak of it. 沒人敢談及此事。
He never dared stay long. 他從不敢多待。
We hardly dared (to) breathe as somebody walked past the door. 有人從門口過時,我們幾乎都不敢喘氣了。
I scarcely dare think of it. 這事我簡直不敢想。
b. 疑問句及條件從句(有時也可借助助動詞):
Dare you interrupt him? 你敢打斷他的話嗎?
How dare you speak to me like that! 你怎么敢對我這樣講話!
How dare he take my bicycle without even asking! 他怎么敢不問一聲就把我的自行車拿走!
I wonder if she dared come home. 不知道她敢不敢回家。
Do you dare tell him? 你敢告訴他嗎?
If you dare speak to me like that again, you will be sorry. 要是你再敢這樣對我說話,你就會后悔的。
Jump if you dare! 你要是敢就跳!
c. 用于I dare say,don't you dare引導的句子中:
I dare say you're right. 我認為你是對的。
I dare say you are British. 我看你是英國人。
You're tired, I dare say. 我想你是累了。
Don't you dare tell my parents about this! 你敢告訴我父母這件事!
Don't you dare touch that vase. 不準碰那花瓶。
I'm going to tell your father about the drugs. "Don't you dare!"“我要把毒品的事告訴你爸?!薄澳愀?!”
2) 作及物動詞的用法:
作及物動詞時可以表示:
a. 敢(做某事)(可用于多類句子):
He dared to walk the tightrope without a net. 他敢不用安全網(wǎng)來踩鋼絲。
He dares to accuse me of dishonesty. 他竟敢說我不老實。
I did not dare to complain. 我不敢抱怨。
I sat at the back, never daring to speak. 我坐在后面,從不敢說話。
Do you dare to suggest that I'm capable of such an act? 你敢說我能做出這樣的事?
b. 敢于面對(嘗試):
He will dare any danger. 他敢于面對任何危險。
He dared the anger of her family. 他敢于面對家人的憤怒。
The actress dared a new way of playing that famous character. 這位女演員敢嘗試以新的方式扮演那個名人。
c. 向…挑戰(zhàn),要某人做一件危險的事:
Can you jump off the wall? Go on, I dare you! 你能從墻上跳下來嗎?來,我要你跳!
Somebody dared me to jump off the bridge into the river. 有人問我敢不敢從橋上跳到河里去。
I dared them to debate with me about it. 我問他們敢不敢和我辯論這個問題。
1) be able to可以跟一動詞,意思和can差不多,有時兩者可以換用:
I'm not able to (can't) answer your question. 我回答不了你的問題。
Are you able to (Can you) type? 你會打字嗎?
When he was young he was able to (could) climb any tree. 小時候他什么樹都爬得上去。
He wasn't able to (couldn't) understand that sentence. 他不懂那句話。
但be able to可用于更多時態(tài),有時不能用can代替:
I shan't be able to come to your wedding. 我將不能來參加你的婚禮。
Since his accident he hasn't been able to leave the house. 他出事以來一直不能出門。
She said she had lost her passport and hadn't been able to leave the country.她說她護照丟了,一直無法出境。
She wasn't sure whether she would be able to get back that week. 她不能肯定那個星期能否趕回來。
2) be able to還可和某些情態(tài)動詞或系動詞連用:
I ought to be able to get in touch with him. 我應當可以和他取得聯(lián)系。
He might be able to find a good hotel. 他或許能找到一家好旅館。
She should be able to offer you some good advice. 她應當可以給你出點好主意。
He seemed able to put complicated thought in simple words. 他似乎能把復雜的思想用簡單的話語說出來。
3) 還可用于非謂語動詞中:
I should like to be able to read the book in the original. 我希望能閱讀這本書的原文。
He much regretted not being able to come to your wedding. 他很遺憾沒能來參加你們的婚禮。
She grasped my hand, not being able to say anything. 她抓住我的手,什么也說不出來。
1) have to的意思接近must,但must強調(diào)說話人的意愿:
We must remember this. 我們必須記住這一點。
You must take good care of her. 你要好好照顧她。
而have to表示客觀上的必要性,??勺g為“(不)得(不)”,否定形式表示“不必”:
You have to have a visa to go to another country. 你到別國去得有簽證。
She has to go to the bank this afternoon. 今天下午她得去銀行。
We have to be careful in such matters. 處理這類事我們得小心。
He has to do a lot of reading. 他得看很多書。
Δ這種結(jié)構(gòu)的疑問式和否定式都借助do構(gòu)成:
Do you have to leave so soon? 你這么快就得走嗎?
Does she have to go with you? 她得和你一起去嗎?
What do I have to do to get a licence? 我要怎樣才能取得駕駛執(zhí)照?
You don't have to get up so early. 你不必起這么早。
She doesn't (didn't) have to answer all those questions. 她不必回答所有那些問題。
Δ還可用于多種時態(tài):
I missed the bus and had to walk home. 我沒趕上巴士,只好走著回家。
We'll have to help him as much as we can. 我們將不得不盡力幫助他。
First I'd have to get my father's consent. 首先我必須取得我爸的同意。
These last few days I've had to take a rest. 最近這幾天我不得不休息了一下。
If it hadn't been for your help, I would have had to leave. 要不是你幫忙,我就得離開這里了。
2) 這種結(jié)構(gòu)可用于被動語態(tài):
All kinds of difficulties have to be overcome. 有種種困難需要克服。
A lot of letters had to be answered. 有大量的信要回。
The whole thing will have to be done all over again. 整件事將不得不重做一遍。
還可和may,might連用:
We may have to cancel the plan. 我們可能不得不取消這項計劃。
They might have to ask her permission to do this. 他們要這樣做可能得請求她的許可。
3) have got to和have to意思差不多:
I've got to be off now. 我現(xiàn)在得走了。
We've got to send her to hospital. 我們不得不送她進醫(yī)院。
Has he got to get himself involved in this affair? 他有必要卷入此事嗎?
She has got to be operated on. 她得動手術(shù)。
1) had better也接近一個情態(tài)動詞,后面總跟動詞原形,表示“最好…”(had??删o縮為'd):
We'd better go before it gets dark. 我們最好趁天沒黑就走。
You'd better take a nap after lunch. 午飯后你最好小睡一會兒。
Hadn't we better take an umbrella? 我們是不是帶把雨傘比較好?
You'd better not talk like that. 你最好別這樣講話。
What had we better do? 我們最好怎么辦?
后面有時可跟不定式的進行式,表示立即做某事:
I think I'd better be going. 我想我最好還是馬上走。
We'd better be getting our clothes ready. 我們最好馬上把衣服準備好。
had有時可以省略:
You better stop arguing. 你們最好別爭論了。
Better not wait for them. 最好別等他們了。
2) had best的用法和had better差不多:
We had best have his opinion first. 我們最好先聽聽他的意見。
I had best be going now. 我最好現(xiàn)在就走。