一般助动词后面都接动词原型
另外,情态动词can, will ,have to ,could, would, should, might, had to,was to, were to,must, ought to等
在用法上,情态动词和助动词一样,后面接动词原型.
只是要注意一些固定短语
have to
be used to
ought to等等