Ответ:

1. doing/writing.

2. written.

3. studying.

4. learnt.

5. teaching.

6. taught.

7. done.

8. found.

9. looking.

10. talking.

11. talked.

12. said.

13. telling.

14. told.

15. told.

16. had.

17. having.

18. spoken.

19. asked.

20. learnt.

21. writing.

22. doing/reading.

23. read.

24. answering.

25. fixed/having.

26. heard.

27. read.

Ответ:

Просто добавляете( - ing) например: doing, writing, studying.....

На который стоит в скобках после to добавляете ing