Odpowiedź:
1.Bill and Sarah were playing in the garden when their mum called them in to have dinner. (they were playing for a long time their mom called them once)
2. Claire was at her friend's house when the earthquake happened. (she was at her friend's house for 3 hours and the earthquake happened for 3 mins so it was shorter)
3.Wanda was watching a street parade when a man grabbed her bag and ran off. (she was watching for a long time, the man grabbed her bag quickly)
4.While we were getting ready for the party we heard a knock on the door. (we were getting ready for a long time the knock was short)