1.He needs some help.
2.Does he need to come?
3.He don't need to come.
(你的問題在于：NEED情態(tài)動(dòng)詞和行為動(dòng)詞的區(qū)別沒有弄清.看一下,下面的內(nèi)容也許會(huì)幫助你區(qū)別NEED情態(tài)動(dòng)詞和行為動(dòng)詞)
一、作情態(tài)動(dòng)詞
1．need作情態(tài)動(dòng)詞無人稱或數(shù)的變化,后接動(dòng)詞原形,多用于否定句和疑問句中.如：You needn't worry.你不必?fù)?dān)心.
2．由need引出的一般疑問句,肯定回答常用must或have to;否定答語常用needn't.如：
—Need I answer the question?我需要回答那個(gè)問題嗎?
—Yes,you must./Yes,you have to.是的,你必須回答./是的,你得回答./No,you needn't.不,不必了.
3．由must引出的一般疑問句,肯定回答用must,否定答語用needn't或don't have to.如：
—Must I do the work now?我必須現(xiàn)在干這個(gè)活嗎?
—Yes,you must /have to.是的,你必須做./No,you needn't /don't have to.不,你現(xiàn)在不必做.
二、作行為動(dòng)詞
need 作為行為動(dòng)詞有人稱和數(shù)的變化,后面可接名詞、代詞、動(dòng)名詞及帶to 的動(dòng)詞不定式；可用于肯定句、疑問句和否定句中,如：She needs help.她需要幫助.I don't need to see the doctor.我不需要看病.—Do you need to go at once?你需要馬上走嗎?
—Yes,I do.是的,我得馬上去.
—No,I don't.不,不用馬上走.