Réponse :
1. The meeting was at nine o'clock. When I arrived at ten, the meeting had finished
2. When we got to the airport, I realized that I had left my passport at home.
3. He didn't realize that he had gone) through a red light, until a policeman stoppedhim.
4. They didn't want to go to the cinema because they had seen the film the week before.
5. Barbara had changed so much so much that I didn't recognize her.
Explications : Past perfect exprime une action antérieure à un prétérit