0)  If +Present Simple, Present Simple

a real condition in the present

If you have a car, you can travel.

1) If +Present Simple (will), Future Simple

a real condition in the future

If I have a car, I’ll travel more.

2) If +Past Simple, would + V1

an unreal condition in the present (+ future)

If I had enough money, I’d buy a car.

3) If +Past Perfect (had + V3), would have + V3

an unreal condition in the past

If I’d had enough then, I’d have bought a car.

4) Mixed Conditional

3+2/2+3

If I had taken that job then, I’d be rich now.

If I were you, I’d had taken that job.