文档介绍：新概念英语第一册must的用法
一、《新概念英语》中的must
在《新概念英语》经典版中，must消失的频率较高，分别消失在第一册第43-46课、第61-66课、第77-80课、第12right away.
have to：She has to go home right away.
再比方：
must：She must attend the meeting yesterday.
have to：She had to attend the meeting yesterday.
2、由于must没有时态的变化，而have to有，所以在句型转换中，要留意两者的区分。如：
1)must
确定句：She must attend the meeting yesterday.
否认句：She needn”t attend the meeting yesterday.
一般疑问句及其答复：Must she attend the meeting yesterday? Yes, she must. / No, she needn”t.
划线局部提问：What must she do yesterday? (假设划线局部为attend the meeting的话)
2)have to
确定句：She had to attend the meeting yesterday.
否认句：She didn”t have to attend the meeting yesterday.
一般疑问句及其答复：Did she have to attend the meeting yesterday? Yes, she did. / No, she didn”t.
划线局部提问：What did she have to do yesterday? (假设划线局部为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“必需”，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. (由于太脏了，我必需要清扫房间。)
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存在以上区分，在must的否认句以及一般疑问句的否认答复中，也常常可以用have to来替换needn”t。如：
确定句：She must attend