Possibility and certainty key:
- can’t, 2. may / might / could 3. must, 4. must, 5. may / might / could, 6. can’t, 7. must , 8.can’t, 9. may / might / could , 10. can’t, 11. may / might / could, 12. can’t 13. may / might / could, 14. must, 15. may / might / could, 16. must / may / might / could, 17. can’t , 18. must, 19. must , 20. may / might / could