Ответ:
1. If we had met Anna, we would have told her everything.
2. It is a pity that Tom has already left.
3. If I were you, I would not buy this car.
4. If I had gone to the meeting yesterday, I would have heard the latest news.
5. If we had a vacation now!
6. If we had not received this letter yesterday, my brother would be at home now.
7. If I knew English well, I would speak with the English yesterday.
8. It is a pity that you did not attend the exhibition.
9. It is a pity that I do not know French.
10. If I didn’t have to work so much today, we would go.
11. If the weather was good yesterday, we would have done. We drove to the park.
12. If I knew his phone number, I would call now. 13. It is a pity that it is raining.
14. If not for his help, I would not work now.
15. If I were you, I would wait.