Réponse:

1. She wrote a letter to her friend, and then, she posted it.

2. I didn't go to school last Friday. I was ill.

3. Did they buy some clothes yesterday ? Yes they bought a pair of trousers.

4. wasn't the steak good ? No it wasn't.

5. The cat jumped the fence when it saw the dog.

6. My cousins didn't enjoy the party.

7. Your parents didn't study English at school. They studied French.

8. I waited for an hour but he didn't "call" ?

9. When did you finish your exams ?

10. She lived there for a few years, but she didn't like the place.

11. They came to our house yesterday but they didn't stay.

12. What did you say ? I didn't hear you.