1. He'll forget number, if he doesn't write it down.
2. If Samantha doesn't hurry up, she'll miss her train.
3. I'm sure he'll understand, if you tell him how you feel. (не уверена)
4. If you don't listen carefully, you won't know what to do.
5. Anita won't dance with you, if you don't ask her.
6. Sam will go back to school tomorrow, if he feels better.