1.need+n.的時(shí)候,意思和want接近：
e.g.He needs money.
It doesn't need explanation.
2.need+to do是指需要做某事,主語是動(dòng)作的發(fā)出者：
e.g.He needs to clean the house.
He doesn't need to clean the house.
3.need+doing也是指需要做某事,不過主語是動(dòng)作的承受著,含有被動(dòng)意：
e.g.The clothes need washing.（這個(gè)形式的否定很少見）
4.此外need還可用作情態(tài)動(dòng)詞,用在含有must do的問句的否定回答中.
e.g.-Must I do all the exercises?
-No,you needn't.(沒必要)