📘 Part of the Complete English Course · Intermediate (B1), week 7
Modal verbs let you show how certain you are: That must be right (I'm sure), it might work (maybe), it can't be true (I'm sure it isn't).
The rules
How sure?
| Modal | Certainty | Example |
|---|---|---|
| must | very sure it's true | She must be tired. She worked all night. |
| may / might / could | possible (maybe) | It might be a good idea, but… |
| can't | very sure it's not true | That can't be right. I paid already. |
Remember
- Modal + base verb: might be, could work (not 'might to be').
- 'Might' is very useful for soft disagreement: That might be tricky because…
- Past possibility: must have / might have / can't have + past participle: He must have forgotten.
Listen and repeat
- That might work, but have we thought about the cost?
- You must be exhausted after that shift.
- It could be the battery.
- That can't be right. The bill was paid last week.
Common mistakes
| Not this | Say this | Why |
|---|---|---|
| It might rain. | No 'to' after modals. | |
| He must be at home. | No 'to'. | |
| It can't be true. | Opposite of must (sure) is can't. |
Check yourself
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Frequently asked questions
When do we use might / must / can't in English?
Modal verbs let you show how certain you are: That must be right (I'm sure), it might work (maybe), it can't be true (I'm sure it isn't). Modal + base verb: might be, could work (not 'might to be').
What are common mistakes with might / must / can't?
Say 'It might rain.', not 'It might to rain.' (No 'to' after modals). Say 'He must be at home.', not 'He must to be at home.' (No 'to'). Say 'It can't be true.', not 'It mustn't be true. (meaning I'm sure it's false)' (Opposite of must (sure) is can't).
What level is this might / must / can't lesson?
It's a Intermediate (B1) lesson, week 7 of the free Complete English Course. It takes about 10 minutes and ends with a quiz.