need做实义动词是“必要,需要”,是及物动词
need做情态动词时,指“必须”.
因无过去式和未来式,故分别用had to , will have to 来代替.
need do sth 中need为情态动词.
need doing sth = need to be done
表示有被动含义.
用need提问回答是:(1)Yes , I need .
(2) No , You needn”t / No , You don”t have to .
详细的看这里了:)~~
http://www.***.com/xll/zhongkao/yy/200601/92433.html