1. If I had known my father had an appointment at the dentist's I wouldn't have taken the car.
2. If my mother had told me she would be late I would have cooked the dinner.
3. If only I had replied for the job sooner I wouldn't have regretted.
4. I wish I wouldn't have bought a second-hand car.
5. If I had know Jack was having financial difficulties I would have helped him.