1. If someone does you a favor, you should do a favor for that person in return

1. I helped Lin fix her flat tire, and she gave mea ride. One good turn deserves another.

2. Jill: Thanks for the ride. Jane: It’s the least I can do after you helped me wash the car last week. One good turn deserves another.

3. Child: I don’t want to help Grandma go shopping. Father: But she helped you with your homework yesterday. And one good turn deserves another.