Modal verbs indicate possibility, probability, ability, permission, obligation or express advice. They include Can, Could, May, Might, Must, Shall, Should, Will, Would.
- don't use an 's' for the third person singular.
- make questions by inversion ('she can go' becomes 'can she go?').
- are followed directly by the infinitive of another verb (without 'to').
We can use verbs such as 'can', 'could' and 'may' to ask for and give permission. We also use modal verbs to say something is not allowed
- May I ask a question?
- Could I have some tea, please?
- Can we go home now?
• POSSIBILITY or PROBABILITY
We can use these modal verbs when we want to make a guess about something. We choose the verb depending on how sure we are. We can use: must, might, could, may, can or shall.
- They may come by car.
- They might be at home.
- If we don't hurry, we could be late!
• OBLIGATION or ADVICE
We can use verbs such as 'must' or 'should', 'have to', 'could' to say when something is necessary or unnecessary, or to give advice.
- You must stop at a red light
- We have to wear a uniform at work.
- You should send an email.
- You could go by train.
We use 'can' and 'could' to talk about a skill or ability.
- She can speak several languages.
- He can swim like a fish.
- I couldn't see you!