need的用法

　　Need(需要) 的用法

　　1.Need作為實(shí)義動(dòng)詞

　　有人稱、數(shù)和時(shí)態(tài)的.變化(在變?yōu)榉穸ň浜鸵蓡?wèn)句時(shí)需借助于助動(dòng)詞) (1)當(dāng)主語(yǔ)是人時(shí)，后可接名詞和動(dòng)詞不定式，即：need sth./ need to do sth. Eg: He needs some help. It's cold outside. You need to wear more clothes. Need后跟不定式且用于否定句中時(shí)，表示“不必”，指沒義務(wù)或沒必要做某事。 Eg: You don't need to do it at once.你不必馬上做那件事情。 (2)當(dāng)主語(yǔ)為物時(shí)，后接名詞或v-ing. Eg: The flowers need water. 這些花需要水。The flowers need watering.這些花需要澆水。

　　2.need作為情態(tài)動(dòng)詞 (注：情態(tài)動(dòng)詞不能獨(dú)立作謂語(yǔ)，必須和動(dòng)詞原形一起構(gòu)成謂語(yǔ)，即need作為情態(tài)動(dòng)詞時(shí)，后面必須跟動(dòng)詞原形)無(wú)人稱、數(shù)和時(shí)態(tài)的變化，常用于否定句和疑問(wèn)句中。Eg: You needn't go this week.這周你不必去。

　　由need引導(dǎo)的一般疑問(wèn)句，肯定回答一般用must，否定回答一般用needn't。Eg: -------Need I come? -------Yes, you must./ No, you needn't 注：由must引導(dǎo)的一般疑問(wèn)句，肯定回答一般用must，否定回答一般用needn't或don't have to Eg: --------- Must I go now? -------- Yes, you must. No, you needn't/don't have to.