Ответ:

2. If I hadn't been on the phone, I would have seen the tree.

3. If I had seen the tree, I wouldn't have crashed into it.

4. If I had had much money, I would have been able to pay for repairs.

5. If I hadn't worn my seatbelt, I would have hurt myself.

6. If I had driven more carefully, I wouldn't have had the accident.