Modals

Can, can't, must, have to for ability and obligation

简介

情态动词是一类特殊的助动词，用来表达能力、可能性、许可和义务。它们不随主语变化，后面永远跟动词原形。

中文里的“能”“可以”“必须”就是类似的概念。英语的情态动词也差不多——“can”相当于“能/可以”，“must”相当于“必须”。好消息是，情态动词不需要变位（不用管什么第三人称加s），所以用起来其实挺简单。

掌握了这些情态动词，你的表达就不再只是简单陈述事实，而是能传达“什么是可能的、什么是被允许的、什么是必须做的”。

主题

本章全部英语语法（13）

• can / can't Expresses ability, possibility, or permission
• must / have to Expresses obligation or necessity
• could (past ability) Expresses past ability or past possibility
• may / might Expresses possibility or asks for permission
• will (future) Expresses future actions, promises, and spontaneous decisions
• going to (future) Expresses planned future actions and predictions based on evidence
• Let's (suggestions) Making suggestions that include yourself
• Shall (offers & suggestions) Offering to do something or making suggestions
• should / shouldn't (Basic Advice) Giving simple advice or opinions
• could (Polite Request) Making polite requests and asking for permission
• would like Polite way to express wants
• May I...? (Formal Permission) Asking for permission formally
• might (Weak Possibility) Expressing something is possible but uncertain