一、用法 从高考及平时各类考试情态动词的推测用法来看,主要有must, should, can (could), may(might)几个词,现对它们的用法按可能性从大到小排列列表如下: 一般式:must/ should/ can/ could/ may/ might do sth. 进行式: must/ should/ can/ could/ may/ might be doing sth. 完成式: must/ should/ can/ could/ may/ might have done sth.