1. What are you (to do) here? - I am (to write) a letter to my friends. 2. Who has (to write) fu article? 3. What language are you (to study)? 4. We have already (to learn) a lot of English words. 5. What is she (to teach) them? 6. Who has (to teach) you to do it? 7. He has just (to do) something for us. 8. Have you (to find) the book? 9. What are you (to look) for? 10. What are you (to talk) about? 11. We have just (to talk) about it. 12. He has just (to say) something about it. 13. She is (to tell) them some interesting story. 14. He has (to tell) us nothing about it. 15. She has (to tell) them some stories about dogs. 16. We have (to have) two lessons today. 17. They are (to have) a meeting. 18. She has not (to speak) yet. 19. They have (to ask) me several questions. 20. He has already (to learn) the rule. 21. I am (to write) an exercise. 22. What is he (to do)? - He is (to read) a newspaper. 23. Have you (to read) any stories by Jack London? 24. I am (to answer) the telephone right now. 25. He has (to fix) his car and now he is (not to have) any trouble with the brakes anymore. 26. You have just to hear) tomorrow's weather forecast

1. What are you doing here? - I am writing a letter to my friends.
2. Who has written the article?
3. What language are you studying?
4. We have already learned a lot of English words.
5. What is she teaching them?
6. Who has taught you to do it?
7. He has just done something for us.
8. Have you found the book?
9. What are you looking for?
10. What are you talking about?
11. We have just talked about it.
12. He has just said something about it.
13. She is telling them some interesting story.
14. He has told us nothing about it.
15. She has told them some stories about dogs.
16. We have had two lessons today.
17. They are having a meeting.
18. She has not spoken yet.
19. They have asked me several questions.
20. He has already learned the rule.
21. I am writing an exercise.
22. What is he doing? - He is reading a newspaper.
23. Have you read any stories by Jack London?
24. I am answering the telephone right now.
25. He has fixed his car and now he is not having any trouble with the brakes anymore.
26. You have just heard tomorrow's weather forecast

Ответ: 1. doing, writing; 2. written; 3. studying; 4. learned; 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. learned; 21. writing; 22. doing, reading; 23. read; 24. answering; 25. fixed, having; 26. heard