Ответ:

1.She was walking in the street when the accident happened.

2.Justin finished his exercises, packed his things, and went home.

3.I saw him in the street yesterday.

4.When I got home, everyone was chatting in the classroom when the door opened and the headmaster had already gone to bed.

5.They entered the room.

6.What did you do yesterday at 6? I got a good mark for the test because I listened carefully to the teacher's explanations.

7.Kevin called you.

8.We decided to make a poster. First, we found some paper and felt-tips and then we started drawing.

9.Fergie was late because she missed the bus.

10.I was checking my messages when someone called me. She lost her glasses yesterday.

11.Granny left my house.

12.I couldn't do my homework because I left my textbook at school.

13.My sister was drawing while my brother was playing with his Transformer toys.

14.He didn't go to the cinema because he had already seen the film.

15We were watching a movie when the phone rang.