Réponse :

1-They were sleeping when the baby started crying

2-She saw an accident while she was cycling to school

3-He was doing his English homework when the computer caught fire

4-She was playing with the dog when it decided to b!te her

5-He was stealing a television when a policeman arrived

6-They were playing basketball when it started raining

7-While she was having a bath, the telephone rung

8-They were waiting for the bus when they saw an UFO

Tu écriras b!te (mordre phrase 4) avec un "i", vu que le site est en français ça me dit  que c'est inapproprié.