A. Unless 5 If / or → If

1. If he doesn't choose his words more carefully, he'll be in trouble. 

 2. You wouldn't speak English well unless you had more practice.

3. Unless he apologizes, I will never invite him here again.

4. If you don't hurry up, you will be late.

5. If you don't right now,  you'll be late for the train.

B. If loại 2

6. If he wasn't old, he could apply for the job.

7. If I didn't drink too much strong coffee, I could sleep.

8. If I had enough free time, I could help my mother with the housework.

9. If he finished his homework, he wouldn't be punished by the teacher.

10. If I had enough money, I could buy that motorbike.

C. If loại 3

11. If the driver hadn't driven so fast, he wouldn't have caused accident.

12. If my brother had left the car key, I could have picked him up at the station.

13. If we hadn't been busy, we would have gone to the concert

14. If my father had earned much money, life would have been easy for us.

15. If he hadn't been careless, he wouldn't have got lost.