16. If he doesn't take any exercises,  he will be unhealthy 
17. If i don't have the right  change,  we can't het the ticket 
18.if you study hard,  you will pass exam
19. If you are impatient,  you will make mistakes 
20.unless they invite me,  i won't come
21.if you walk to the park,  it will take you 5 minutes 
22.if you leave me alone, i won't call the police 
23. If it snows , the children won't go to school 
24.if you tell me the whole truth,  i will help you 
25.if you do tell lies to your boss,  you will be fired at once