Думаю так.
1. If it was cleverer, it wouldn't go to the wood yesterday. 2. If it didn't send this letter yesterday, my brother would be now at home. 3. What we now would do if mother didn't bake pie yesterday? 4. It is a pity that you didn't hear Rachmaninov's music. If you heard it, you would know what is the remarkable composer. 5. I am sure that all would be glad if evening took place. 6. It so changed! If you met him, you wouldn't recognize him. 7. If I was on your place, I would consult to parents. 8. If the tram now approached, we wouldn't be late. 9. If he knew that it will upset you, he would be more careful. 10. If you to me helped to solve this problem, I would be very grateful to you. 11. It is a pity that didn't come to our mind earlier to look for the book in library. We would make work in time and would be now already free. 12. It is a pity that we had so few lessons. If we worked more, we would know language better. 13. If he regularly didn't visit sports trainings, he wouldn't achieve such success on competitions. 14. If you warned me in advance, I would already be in Moscow. 15. It is a pity that it already left. If you called earlier, it would be now here.