其他情态动词举例：
can (could), may (might), must, need, ought to, dare (dared), shall (should), will (would) must
四大分类
①只做情态动词:may, might, must..
②可做情态动词又可做实义动词：如：need, dare,can
③具有情态动词特征：have(had,has) to,used to, ought to
④可做情态动词又可作助动词：如：shall(should),will(would)
注意：mustn't代表强烈禁止 must表示主观，have to表示客观。美式英语中常用must not 而不用 mustn't. mayn't,mightn't和shan't也很少用