She won't be angry if you tell her the truth.
If I don't see you later, I will see you on Friday.
You won't have time if you don't start now.
If you tell me your secret, I won't tell anybody.
If I don't write it down, I won't remember it.
You won't pass if you don't study.
If you find something in a shop that you really like, they won't have it in your size.
If you take Vitamin C, you won't get a cold.
Jack will be sad if he don't see you tomorrow.
If you don't remember to take an umbrella, it will rain.
If I learn, I'll pass the exam. 
If we don't hurry up, we will be late. 
What will you do if you don't go to London? 
If you ring this number, nobody answers.
If you drink, don't drive.