4. When Tom was crossing the street, he fell.
5. When we were walking about in the forest, we saw a hare.
6. When I was washing the floor, I found my old toy under the sofa.
7. When I was playing in the yard, I suddenly saw my old friend.
8. When Nick came home, his brother was playing with his toys.
9. When I saw my friends, they were playing football.
10. When I opened the door, the cat was sitting on the table.
11. When granny was reading a book on the sofa, she fell asleep.
12. Sylvia was making her breakfast when the doorbell rang.
13. The police officer saw the accident when he was driving to work.
14. My sister was singing while she was doing her homework.
15. My brother was drinking coffee while he was doing his homework.
Ответ: смотри решение