need可用作实义动词,表示“某人需要做某事”时后跟动词不定式。如: He is too tired. He needs to have a good rest. 也可用作情态动词,后跟动词原形,但一般只用于否定句或疑问句。如: -Need you have a rest? -No, thanks. I'm not tired. I needn't have a rest. need doing通常表示“需要被做”。如: This old bike needs repairing.
第2个回答 2011-08-21
1.need do -- need 是情态动词,加动词原形
2.need to do ---need是实义动词,加动词不定式 eg:we need finish our homework on time. we need to finish our homework on time. 我们要准时完成家庭作业. 两句话意思相同,语法不同。
3.need doing ---需要被做某事 表示被动 The clothes need washing. 衣服需要被洗