这只是两种不同的表达方式.如：1.We have got a lot of fruit.So we don't need to buy any.（need做行为动词） 2.All you need do is to read the scentences again and again.（need做情态动词） 3.Don't worry,you need not do them.(need做情态动词）当用Must 提问,作否定回答时,常常用needn't.如：Must I take off my shoes?
