Ответ:

№ 4

1. While the thief was climbing up the ladder, the police arrived

2. When the teacher walked into the classroom, the boys were fighting

3. Was you playing loud music when I phoned you?

4. While Sam was riding his bike in the park, he lost his mobile

№ 5

1)While sam was running he dropped his money

2) when we saw the thief he climbed through the window

3) they were traveling around the world when they lost their bags

4) my little brother ran into the kitchen while i was making a dinner

5)they were sleeping when the fire started

6) what were you doing when I phoned?

(вроде так)