情态动词使用方法详解
情 态 动 词 定 义
    情态动词是一个本身有一定词义，表示说话人情绪、态度或语气动词，但不能单独作谓语，只能和其它动词原形组成谓语。 We can be there on time tomorrow. May I have your name?  Shall we begin now? You must obey the school rules.  
can / could
may / might
must
shall / should
will / would
need
dare
ought to
had better
cannot / could not
can’t / couldn’t
~ + not
mayn’t / mightn't
~ + not
mustn’t
~ + not
shan’t / shouldn’t
~ + not
won’t / wouldn’t
~ + not
needn’t
~ + not
daren’t
ought not to
oughtn’t to
Had better not
’d better not