Modals of deduction
Use must, might, may and cannot to express how certain you are about a present situation.
Learning goal: Modals of deduction
Distinguish strong certainty, possibility and logical impossibility.
In a nutshell
Use must, might, may and cannot to express how certain you are about a present situation.
When do we use it?
Distinguish strong certainty, possibility and logical impossibility.
Pattern
Form
Use must for a strong positive deduction, might/may/could for possibility and can’t for a strong negative deduction.
- She must be tired.
- He might be at home.
- That can’t be true.
Examples
Key contrast
Read the whole context and identify the time, meaning, noun type or sentence structure before choosing.
Watch out
Common mistakes
She must to be tired.→ She must be tired.It can be impossible.→ It can’t be true.
Key takeaway
Remember
Use must, might, may and cannot to express how certain you are about a present situation.
Self-check
Quick check
- Find the grammar clue.
- Check the subject and verb form.
- Confirm that the answer fits both structure and meaning.
Put it into practice
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A short interactive practice session with instant feedback — about 10 questions calibrated to C1 Advanced.
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