Ответ:

  1. If I had paid attention, I wouldn’t have crashed the car.
  2. If I had much money, I would be able to pay for the repairs.
  3. If I hadn’t borrowed my friend’s car, I wouldn’t have had an accident.
  4. If I drive more carefully in future, I won’t have another accident.
  5. If I were an experienced driver, I would be a very good driver.
  6. If I had seen the tree, I wouldn’t have crashed into it.