Ответ: 14. Helen swimed very well. 15. He often gave promises but seldom kept them. 16. We put our books on the shelf. 17. In cold weather we put on warm coats. 18. Mary took her younger sister to school. 19. These students knew English grammar well. 20. He often told us funny stories. 21. Nick’s house standed in a big street. 22. He always knew what to do. 23. She ate only vegetables. 24. My friend speaked two foreign languages.

Ответ: В задании Поставить в Past Simple. А добавление -s -es характерно для Рresent Simple