Unreal or unlikely present/future results: If + past, would + base
If + past simple, would + base verb
If + past simple, wouldn't + base verb
What would you do if + past simple?
💡 Use were for all subjects in formal style (If I were you). Don't use will in the if-clause.
✓If I were you, I'd see a doctor.
✗If I am you, I will see a doctor.
Second conditional uses past + would.
✓If they had more time, they'd help.
✗If they have more time, they'd help.
Use past in the if-clause.
✓What would you do if you lost your keys?
✗What will you do if you lost your keys?
Use would in result, past in condition.