Could, should, would

Modals (could, should, would and others) add meaning to a main verb: ability, duty, possibility, politeness. The same modal can do different jobs, so read the context.

**Could:**

• past ability: 'I could hear the audience.'
• possibility: 'It could rain.'
• unreal ability: 'If I had wings, I could fly.'
• polite request: 'Could you help me?'
• suggestion: 'We could take the bus.'

**Couldn't:** inability ('I couldn't open the jar') or impossibility ('It couldn't be helped').

**Should:** advice or duty ('You should rest'), or probability ('They should be home by now').

**Would:** prediction ('I knew I would win'), polite request ('Would you close the door?'), past habit ('As a child, I would swim every day').