白易礼:大学英语四级考试语法笔记25
日期:2008-10-12 15:17

(单词翻译:单击)

  2、must与 have to的比较。 Must 强调主观意志,也就是说,必要性来自说话者的主观意志。 have to 强调客观因素。例如:
  He must stop smoking. 他必须戒烟。(说话人认为他必须)
  This is an awful film. ?We really must go. 这部电影糟透了-我们一定要离开这里。(说话人认为必须)
  You have to go and see the boss. 你一定得去见见老板。(客观因素)
  Catholics have to go to church on Sundays. 天主教徒星期天必须去做礼拜。(客观因素,如教规等 )
  注意:must not表示“绝对不可”; don’t have to(或 haven’t got to )表示“不必,没必要”,两者意思极为不同。英国英语中常用needn’t来代替 haven’t got to 或don’t have to,如:
  You mustn’t tell Jenny. =Don’t tell Jenny. 你一定不要告诉珍妮。
  You don’t have to tell Jenny. =You can if you like but it isn’t necessary. 你不必非要告诉珍妮。
  3、need 作为情态动词与行为动词的区别。作为情态动词,need 无过去式和将来时,故用had to, will have to替代,主要用在否定句、疑问句、条件句中,意思是“有必要”。例如:
  He need not come at once. 他不必马上就来。
  If you need go there, please tell me now. 如果你需要去那儿,请告诉我。
  Need he come at once? 他必须马上回来吗?
  (回答要用must, have to, ought to, should等。例如:Need he come at once? Yes, he must/ought to /should/has to. No, he needn’t /doesn’t have to /mustn’t.)needn’t have done表示“本来不必做某事而实际上已经做了”。例如:
  We needn’t have waited for him. 我们本来不必等他的。(实际上已等他了)
  用作实义动词时,need可用于肯定句、 否定句和疑问句,是“需要”之意。如:
  You need to wash your hands. 你需要洗手。
  Does he need to take the medicine four times a day? 他需要每日服药四次吗?
  We didn’t need to see him at all. 我们根本不必要看他(实际上也没去看他,请比较needn’t have done的用法)
  need做实义动词时,后面的宾语如果是动名词,用主动形式表示被动意义,如果是不定式的被动形式,来表示被动意义。类似need的这种用法,还有require, want等。例如:
  The dinning room needs cleaning every day. =The dinning room needs to be cleaned every day. 食堂需要天天打扫。
  My shoes need repairing. = My shoes need to be repaired. 我的鞋需要修理。
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