11. This bone (to give) to my dog tomorrow. 12. We (to invite) to a concert last Saturday. 13. My question (to answer) yesterday. 14. Hockey (to play) in winter. 15. Mushrooms (to gather) in autumn. 16. Many houses (to burn) during the Great Fire of London. 17. His new book (to finish) next year. 18. Flowers (to sell) in shops and in the streets. 19. St. Petersburg (to found) in 1703.