Modal verbs · Grade 8
Modal verbs (can, could, may, might, must, should, will, would) go before another verb to show ability, permission, possibility, advice or obligation. They never change: no -s, no -ed, and the verb after them is always the base form, without to.
Key facts
- Ability: I can swim. In the past: I could read when I was four.
- Permission: Can I go out? May I sit here? (more polite).
- Possibility: It might rain. She may be late. That could be true.
- Advice: You should rest. You shouldn't shout.
- Obligation: You must wear a helmet. Not allowed: You mustn't run. Not necessary: You don't have to come.
- Form: She can swim. (not cans, not can swims, not can to swim). Negative: can't/cannot, won't, shouldn't, mustn't.