Ответ:

1. When we arrived, Kate had already served the dinner. 2. The garden was white, it had been snowing heavily during the night. 3. The boy said that he smoked for some years, but he has just decided to give it up. 4. They had  been sailing for a week when they runned into a terrible storm. 5. We decided that we need a rest as we had been driving since early morning. 6. Bob was walking a bit unsteadily. It was evident that he was drunk. 7. They have been saving money for the whole year before they decided to go to Sicily, as they never were there before. 8. She was very young. The reporter wondered how long she had been working as a model. 9. I decided to call my relatives as we had not been speaking to each other for quite a long time. 10. The agent informed us that nobody had not been living in that house for the last five years. 11. We have lived in Novgorod for a long time when the war broke out. 12. In the evening we went to visit Barbara as we had not seen her new baby yet. 13. The boxer was happy - he won the last round! After all, he trained hard before the match.