Помогите раскрыть скобки с помощью past simple и past continious…

13. — What were you doing when you broke your leg? — I was snowboarding.14. I was studying while he was making dinner. 15. While Ellen was reading, Tim was watching television. 16. Every Sunday last year I was in church. 17. When she was young, she usually went to work on foot. 18. When I was a teenager, I visited a lot of dances.