如题所述
一、《新概念英语》中的must
在《新概念英语》经典版中,must出现的频率较高,分别出现在第一册第43-46课、第61-66课、第77-80课、第125-132课以及第二册第17课、第41课、第65课、第89课。
must比较常见的用法是:表义务或要求等的“必须”;表猜测的“肯定,一定”。
二、表义务或要求等
这时,must表示“必须”。如:
肯定句:He must have some water after the heavy work.
否定句:He needn't have any water after the heavy work.
一般疑问句及其回答:Must he have any water after the heavy work? Yes, he must. / No, he needn't.
划线部分提问:What must he do after the heavy work?(假如划线部分为have some water的话)
【注意】
(一)mustn't与needn't
很多学生一说到must的否定,首先想到的一般都是mustn't。所以,老师需要提醒学生注意:must表必须时的否定形式是needn't(不必),而不是mustn't(禁止,不能)。
(二)must与have to
虽然have to(不得不,必须)经常被归到情态动词里,但其实have to并不是情态动词,这里的have其实是实义动词,从句子功能来讲,就跟work或play等动词的基本用法是一样的。它与must的区别主要有:
1、must没有时态、人称和数的变化,而have to有时态、人称和数的变化。如:
must:She must go home right away.
have to:She has to go home right away.
再比如:
must:She must attend the meeting yesterday.
have to:She had to attend the meeting yesterday.
2、因为must没有时态的变化,而have to有,所以在句型转换中,要注意两者的区别。如:
1)must
肯定句:She must attend the meeting yesterday.
否定句:She needn't attend the meeting yesterday.
一般疑问句及其回答:Must she attend the meeting yesterday? Yes, she must. / No, she needn't.
划线部分提问:What must she do yesterday? (假如划线部分为attend the meeting的话)
2)have to
肯定句:She had to attend the meeting yesterday.
否定句:She didn't have to attend the meeting yesterday.
一般疑问句及其回答:Did she have to attend the meeting yesterday? Yes, she did. / No, she didn't.
划线部分提问:What did she have to do yesterday? (假如划线部分为attend the meeting的话)
3、must多表示主观需要或责任感的驱使,认为有必要或有义务去做某事,一般译为“必须”,而have to多表示客观存在的环境所限,即客观要求而无奈为之,一般译为“不得不做某事”。如:
主观认为、无人*:I must clean the kitchen because it is too dirty. (因为太脏了,我必须要打扫房间。)
客观所逼、不得不做:I have to do my homework now.(我现在不得不做作业。)
4、尽管have to与must存在以上区别,在must的否定句以及一般疑问句的否定回答中,也经常可以用have to来替换needn't。如:
肯定句:She must attend the meeting yesterday.
否定句:She needn't/doesn't have to attend the meeting yesterday.
一般疑问句及其回答:Must she attend the meeting yesterday? Yes, she must. / No, she needn't/doesn't have to.
三、表猜测
我们在“情态动词can的考点用法”一文中,已经提到,can't表达的是否定猜测,而must则表示肯定猜测,意思是某人或某物一定或肯定会怎么样。
与can't一样,must主要用来表示对现在时间或是过去时间发生的事情的肯定猜测。
(一)对现在时间的猜测
此时,must可以用来表示对现在的状态或动作进行猜测。如果是状态,must后面直接跟表状态的谓语动词即可;如果是动作,must后面的谓语动词则要采用be doing的形式。如:
状态:He must be over 40 years old. (他肯定有四十多岁了。)
动作:He must be reading in the library now. (他现在肯定正在图书馆看书。)
(二)对过去时间的猜测
此时,must后面的谓语动词如果是状态,则采用“must have+表状态的动词的过去分词”;如果是动作,则采用“must have done”的形式;如果是过去进行的动作,则采用“must have been doing”的形式。如:
状态:He must have been in the bathroom when I called him last night.
动作:He must have finished his homework before dinner yesterday.
过去进行:He must have been listening to loud music, for he didn't answer my call.
四、特殊用法
(一)表偏偏
此时,must表达的是说话者不耐烦的语气或是与说话者愿望相反的情况。如:
Why must you come in at this moment? (你为什么偏偏在这个时候进来?)
(二)用作名词
must也可以直接用作普通名词,表示“必须做的事,必需的东西”。如:
A raincoat is a must in the rainy season. (在雨季雨衣是必备之物。)
His new novel is a must for all lovers