本文讨论情态动词的某些惯用结构,包括情态动词(除shall外)接不定式完成式的两种惯用结构;把时间推向过去和本来如何但实际上并未如何的用法;本文也讨论了关于“cannot+help+动名词”,“cannot+but+动词原形”以及“may/minght as well” 和“may/might well”的用法及合义.鉴于大学生对“wouldrather”和“had better”及其变体的用法和理解上尚存在一定的困难,所以.对这两种结构也进行了必要的阐述. This article discusses some of the usual structures of modal verbs, including the two conventional structures of modal verbs (except those outside) followed by infinitive completions; the timing of past and original but not actually used usages; and the article also discusses About the usage and meaning of “can not + help + gerund”, “can not + but + verb prototype” and “may / minght as well” and “may / might well” Variants usage and understanding there are still some difficulties, so the two structures are also necessary to elaborate.