2/ if i haven't been on the phone, i would have seen the tree

3/if i have seen the tree, i wouldn't crash into it

4/if i have got much money (или enough money, как хочешь), i would be able to pay for repairs

5/if i didn't wear my seatbelt, i would hurt myself

6/if i will drive more carefully, i wouldn't have another accident (или i wouldn't cause another accident)