Past Modals


Modal Verbs: Speculating about past events





100 % certain

We often speculate, or make “best guesses”, about past situations based on facts that we have. The modal that we choose depends on how certain we are about our speculation. Affirmative


Must have
Had to have
May have
Might have
Could have



Can’t have
Couldn’t have
Must not have
May not have
Might not have


0% certain


When you are almost 100 percent certain that something was possible, use must have or had to have.

The statues are very big.

· They must have been hard to move.


When you are less certain, use may have, might have, or could have.

The islanders were able to carve the stone.

· The stone may have been quite soft.



When you are almost 100 percent certain that something was impossible, use can’t have or couldn’t have. ·   The islanders couldn’t have moved the stone! It was too heavy.
When you are slightly less certain, use must not. ·   They must not have moved it without help.
Use may not have or might not have when you are less certain. ·   The islanders might not have moved the statues over land. They could have used boats.


There is a man badly injured in the hospital. Complete what his friends are saying about him, using each of these verb forms.

couldn’t      may have       may not         could         may       might have


“He __________ be in hospital for weeks.”

“He __________ recover completely.”

“But it ___________ be worse. He ____________ been killed.”

“This is a very good hospital. He ___________ get better medical treatment anywhere else.”

“The other car was on the wrong side of the road. The driver ___________ been drunk.





Created by Adriane de S. S. Romano



2. Exercise

3. Exercise (present & past)

4. Exercise (present & past)

5. Exercise (present & past)

6. Exercise (present & past)

7. Modal to problem solve

8. Song - The day before you came

9. Implied Meaning of Past Modals

10. Use of "should have / should not have"

11. Use of "must have / must not have"

12. Use of "may have / may not have"

13. Past Modals, Review

14. Past Modals - Class activity - Teacher's notes