need在英語(yǔ)中用法有哪些
need在英語(yǔ)中用法有哪些
“need”既可以作情態(tài)動(dòng)詞，也可以作實(shí)義動(dòng)詞，扮演雙重角色，但是它們的用法不同，比較復(fù)雜，是升學(xué)考試中出題人鐘愛(ài)的一個(gè)考查點(diǎn)。
作為情態(tài)動(dòng)詞的“need”的用法與其他情態(tài)動(dòng)詞“can”，“may”，“must”的用法基本相同：沒(méi)有非限定形式，即沒(méi)有不定式、-ing分詞或-ed分詞等形式;第三人稱單數(shù)現(xiàn)在時(shí)沒(méi)有詞形變化;下面是學(xué)習(xí)啦小編整理的一些關(guān)于need在英語(yǔ)中用法，歡迎大家閱讀！
need在英語(yǔ)中用法有哪些?
一、NEED與句子類型
(本條可參照ANY的用法。)
NEED可用于：
1.否定句/含有否定意義的句子
1)否定句
含not/hardly/never/nobody等詞語(yǔ)。
I needn’t say anything.
He need hardly advise me.
You never need tell me this or that.
Nobody need help me.
I don’t think he need come.(否定轉(zhuǎn)移)
注：NEEDN’T的意思其實(shí)有三種，即不必要/不一定/不應(yīng)該，視具體語(yǔ)境而定。
2)含有否定意義的句子
含only/but/all/before/than等詞語(yǔ)。
He need only wait here.
You need but consider the matter to understand its importance.
That’s all that need be said.
Do not stay longer than you need.
There was another hour before I need go out into the cold.
2.疑問(wèn)句/表示疑問(wèn)的從句
1)疑問(wèn)句(包括否定疑問(wèn)句)
Need he say it again?
2)表示疑問(wèn)的從句
I wonder whether/if I need see her.
3.條件句
含if/unless等詞。
If he need come, he will.
本條要點(diǎn)簡(jiǎn)單概括起來(lái)就是，NEED不能用于肯定句。以下的各種用法也遵循這條規(guī)則。
二、NEED與時(shí)態(tài)
1.現(xiàn)在時(shí)
NEED常用于現(xiàn)在時(shí)。
You needn’t stay.
2.將來(lái)時(shí)
You needn’t have your blood pressure taken tomorrow.
3.過(guò)去時(shí)
NEED的過(guò)去式仍然是NEED。
1)過(guò)去時(shí)間由一過(guò)去時(shí)間狀語(yǔ)表示
He need not come yesterday.
2)過(guò)去時(shí)間由另一過(guò)去時(shí)動(dòng)詞表示。
All he need do was to inquire.
It was clear that he need never trouble to get up at seven again.
I told him he needn’t be in a terrible fix.
注：表示過(guò)去的NEED常用于間接引語(yǔ)中。
(本條可參照must的用法)
三、NEED與虛擬語(yǔ)氣
1)NEED用于虛擬條件句
(本條可參照虛擬條件句的構(gòu)成及用法。)
If money were useless, we need not struggle for it.
If you had been careful enough, you need not have suffered.
注：本條用法較為少見(jiàn)。
2)NEED單獨(dú)使用：NEEDN’T HAVE DONE
(本條可參照SHOULDN’T HAVE DONE的用法。)
You need not have worried.
注：NEED HAVE DONE的形式較為少見(jiàn)
Need you have scolded him so severely for his bad work? He had done his best.(否定意味)
He need have gone and sent that letter in person.(實(shí)際上沒(méi)有做)
四、NEED與推測(cè)
NEEDN’T表示“不一定”。
(本條可參照must/can的用法。)
1)NEEDN’T+BE
It needn’t be hot in Florida now.
對(duì)比：
It can’t be hot in Florida now.(一定不)
It must be hot in Florida now.(一定)
2)NEEDN’T+HAVE DONE
He need not have seen much of the world, though he is an old man.
對(duì)比：
He can’t have seen much of the world, for he is just a little boy.
He must have seen much of the world, for he has been traveling so widely.
五、NEED與問(wèn)句
1)反意疑問(wèn)句的構(gòu)成
You needn’t go, need you?
2)答句的構(gòu)成
--- Need he go?
--- Yes, he must/has to/needs to.
--- No, he needn’t.
(本條可參照must的用法)
六、情態(tài)動(dòng)詞NEED與實(shí)義動(dòng)詞NEED
1)使用范圍
作為實(shí)義動(dòng)詞的NEED有人稱、數(shù)和時(shí)態(tài)的變化，使用范圍更為廣泛，不受句子類型和時(shí)態(tài)的限制。在肯定句、過(guò)去時(shí)和將來(lái)時(shí)的句子中，一般使用作為實(shí)義動(dòng)詞的NEED。
He needs to see a doctor straightaway.(此處needs to不能換做need，因?yàn)楸揪涫强隙ň?
Will he need to start earlier?
注：
NEED TO BE DONE與NEED DOING可以互換，后者更為常用(這里的NEED均為實(shí)義動(dòng)詞)。
2)含義差別
NEEDN’T HAVE DONE與DIDN’T NEED TO DO表示“不必要”的時(shí)候，在意義上有所差別，前者表示“本不必做……”，實(shí)際上已經(jīng)做了(NEED為情態(tài)動(dòng)詞);后者單純地表示“不必做……”(NEED為實(shí)義動(dòng)詞)。