Overview
Modal verbs backshift in reported speech: will → would, can → could, may → might, shall → should, must → had to (for necessity). Modal verbs that do not change: would, could, should, might, ought to (these are already past/hypothetical forms and cannot backshift further).
Modal Backshift
- will → would
- can → could
- may → might
- must → had to (obligation) / must (logical deduction)
- shall → should
No Change Modals
- These modals stay the same in reported speech:
- wouldHe said he would come. ✓
- couldShe said she could help. ✓
- shouldHe said we should wait. ✓
- mightShe said it might snow. ✓
- oughtHe said she ought to rest. ✓
Tricky: Must
- must for obligation → had to:
- Direct'You must submit the form today.'
- ReportedShe said I had to submit the form that day.
- must for deduction → stays must:
- ReportedHe said it must be a mistake.
When to use
Business
She said the team would present the findings.
Medical
The doctor said I had to take the medication twice daily.
News
The spokesperson said they might announce a decision.
Academic
The professor said students should cite all sources.