must 和 have to must 和 have to 都可以表示“必须 .但有几点区别: (1)must 强调“内在的职责 .“义务 .而have to 强调“外界压力 .“不得已而为之 . (2)have to可用于多种时态.而must一般用于现在时.其过去时与将来时分别由had to与shall / will have to代替. (3)在回答must引起的问题时.如果是否定的答复.不能用mustn’t.而要用needn’t或don’t have to.因为mustn’t是“一定不要 .“一定不能 的意思.例如: 1)You must come to the classroom before eight. 2)It is raining hard outside, but I have to leave now. 3)“Must we do it now? “No, you needn’t. 【查看更多】
