The document explains the use of modals of deduction in English, detailing how to express certainty and uncertainty about present and past situations. It covers the use of 'must' for strong certainty, 'may/might/could' for possibilities, and 'can’t' for strong negation. Examples are provided for both present and past tense applications of these modals.

1. Modals of Deduction

2. CAN’TMUST
COULD
MIGHT
MAY


3. (+) Must
• We use ‘must’ when we feel 100% sure that
something is true because we have strong
evidence about the information.
Present Tense
s + must + verb (base form)

4. She must be furious!

5. His parents must be rich!

6. (+) Must
• We use ‘must’ for the past when we feel 100%
sure that something happened in the past.
Past Tense
s + must have + past participle

7. They must have had a big party!

8. The couple must have gotten married!

9. (+) May / Might / Could
• We use may/might/could when we are not
sure about something but we think it is
possible.
Present Tense
s + may/might/could + verb (base form)

10. She may be lonely!
She might be lonely!
She could be lonely!

11. (-) May not / Might not / Could not
• We use may not/might not/could not when we
think that something is not exactly true.
Present Tense
s + may not /might not /could not + v (base form)

12. They might not be a couple!

13. (+) May/Might/Could
• We use may/might/could in the past when we
feel unsure about what happened in the past.
Past Tense
s + may have + past participle
s + might have + past participle
s + could have + past participle

14. • He could have been fired!
• He might have gotten into a
fight with someone.
• He may have had a bad day.

15. Can’t
• We use can’t or cannot when we feel 100%
sure that something is NOT true because we
have strong evidence about the information.
s + can’t + verb (base form)

16. He can’t be cold!

17. I’m shocked! You can’t be serious!

18. Can’t
• We use can’t or cannot in the past when we
feel 100% sure that something is NOT true
about a past situation.
s + can’t have + past participle

19. Maria can’t have been sick yesterday!
I saw her playing tennis in the morning and
soccer in the afternoon!

20. Write modals of deduction for the pictures below!
MUST: 1 Present & 1 Past

21. Write modals of deduction for the pictures below!
CAN’T: 1 Present & 1 Past

22. Write modals of deduction for the pictures below!
MAY/MIGHT/COULD:
1 Present & 1 Past