Can could must should may might
He can not He cans — the verb stays the same.
| Modal | Main use | Example |
|---|---|---|
| can | ability | I can drive |
| could | past ability / polite request | Could you help? |
| must | strong obligation | You must stop |
| should | advice | You should rest |
| may/might | possibility | It might rain |
After a modal the next verb is always in base form.
They express less certainty than 'can' and 'may'.