1. If he arrives tomorrow, we will visit you together.
2. If he arrived tomorrow, we would visit you together.
3. If he had arrived yesterday, we would have visited you together.
4. If you are more careful, you will not make these mistakes..
5. If he was/were more careful, he wouldn't make these mistakes.
6. If he had listened to the explanation carefully, he wouldn't have made these mistakes.
7. If he was/were a good driver, he wouldn't have had a car accident.
8. If you had apologized, you wouldn't have felt so confused.
9. If I wasn't/weren't so busy, I would accept your invitation but unfortunately I have a lot of work to do.