情态动词难点must和have to的用法区别_.doc

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1、情态动词难点must和have to的用法区别_(I) must表示 必须、一定要 ，多指情况,指说话人的主观语气。其否定形式mustn t表示 禁止 You must finish the project by Friday.周五前你必须完成任务。Children must not play with fire.儿童不准玩火。【温馨提示】在回答由must引起的一般疑问句时，如果是否定的答复,通常不能用mustn t,而要用needn t或为don t have to（因为mustn t有绝对禁止的含义）。Must we turn in our plan this week?我们必须这个星期上

2、交我们的计划吗？Yes ,you must?是的，你们必须。No,you needn t/don t have to.不，你们不必。(2)must 和have to的区别：must 只有-种形式,have to有数和时态的变化（如：has to，had to,will have to ); must 的否定式为mustn t,have to的否定式要借助助动词do的某种形式 (如:don t have to，doesn t have to，didn t have to. )My cousin has to practise the violin every night.我表妹每天晚上得练小提琴

3、。I shall have to go there next week.我下星期必须去那儿。两个词意思相近，但must更强调说话者的主观 虽调客观上的必要性，意为 不得不 。 英国英语中常用have got to 替代 have to。I have to be off now. My mum is waiting for me. ( = I have got to be off now.)现在我得走了，妈妈在等我。The little boy has to do lots of housework，for his parents have been suffering from illness

4、. (= The little boy has housework,.)小男孩不得不做很多家务活，因为他父母一直都在患病（3）表示推测，此时常意为 一定是、准是 ，常指 有把握的推测。这种用法只能用于肯定句The light is on,so he must be at home.灯亮着，所以他肯定在家。Look at his new car. He must have earned a lot of money (表示对过去的推测）看他的新车。他肯定赚了许多钱。（4）表示 扁偏，非得要 。Must you waste so much time? 你非得浪费这么多时间吗？Why must it rain on Sunday?为什么偏要在星期天下雨？If you must smoke,please go outside the room.如果你非要吸烟，请去外边吸。（5）表示强调，此时常用于口语中，表示说话者坚定的态度I must say ,you re looking extremely well.我得说你看起来极好。I must admit, I have been looking forward to it.我得承认我一直盼望着它。第 3 页 共 3 页