Expressing degrees of certainty: may, might, could, must
Subject + modal + base verb (She might come) / modal + have + V3 for past
Modal + not + base verb (He must not be there) / modal + not + have + V3
Modal + subject + base verb? (Could it be true?)
💡 No 'to' after modals. Use have + V3 for past probability.
✓She might join us.
✗She might to join us.
No 'to' after modals.
✓He must be tired.
✗He must to be tired.
Base verb after must.
✓They may have left early.
✗They may left early.
Past possibility uses have + V3.
✓He can't be serious.
✗He cannot to be serious.
No 'to' after cannot.