1 need 作情態(tài)動詞用時,意為“需要”,如can一樣,沒有人稱、數(shù)和時態(tài)的變化,后跟動詞原形。疑問句中need 放主語前,否定句為need not。情態(tài)動詞need 常用于疑問句和否定句中。
He need not come at once. 他不必馬上來。
Need he come at once? 他需要馬上來嗎?
She needn't be told. 沒有必要告訴她。
It needn't be talked about. 這沒有必要再說了。
A: Need I go there? 我必須去那里嗎 ?
B: Yes, you must . 是的,你必須去 。
B: No, you needn't . 不,不必的 。
2 need 作行為動詞用時,為及物動詞,同make等行為動詞一樣,有人稱、數(shù)和時態(tài)的變化,疑問句和否定句要用助動詞do等。行為動詞need 后可跟名詞、代詞、不定式、動名詞等。
He needs your help. (正)他需要你的幫助 。
He need your help. (誤)
You don't need to go there. (正)你不必到那里去 。
You don't need go there. (誤)
You needn't go there. (正) (本句中的needn't為情態(tài)動詞否定式 )
Does he need to come early? (正)他需要早點來嗎 ?
Does he need come early? (誤)
Need he to come early? (誤)
Need he come early? (正) (本句中的need為情態(tài)動詞 )
These shoes don't need repairing . (正)這些鞋子不需要補 。
These shoes needn't repairing . (誤)
These shoes don't need to be repaired . (正) (本句中的need為行為動詞,后跟不定式被動式 )
3 needn't have done 表示“本不必做某事,但卻做了”。
You needn't have done it yourself. 你本來用不著自己做的。
He needn't have sold the car. 他本不必把汽車賣掉的。