Ответ:

1. If it rains tomorrow, I will stay at home.

2. Unless you finish your homework, you cannot watch TV.

3. If I had known about the traffic, I would have left earlier.

4. If you study hard, you will pass the exam.

5. Unless you have a ticket, you cannot enter the concert.

6. If I were you, I would take a break and relax.

7. If we leave now, we will arrive on time.

8. Unless you save money, you cannot buy a new car.

9. If you eat too much, you will feel sick.

10. If I see him, I will tell him to call you.

11. Unless you wear a helmet, you cannot ride a bike.

12. If you don't hurry, you will miss the train.