6. has worked

7. have played

8. Have you seen

9. Have... taught

10. haven't seen

Ex2.

1. I have played guitar since I was 16.

2. They've never visited the Greek island before.

3. We've already been to rock concert.

4. She has just arrived.

5. He has lived here for two years.

6. She hasn't still phoned her mother.

7. It has been snowing since this morning.

8. Tourist has been coming to Lizibia since the 1960s.

Ex3.

1. is sleeping

2. eat

3. is running/ wants

4. sets

5. is

6. am doing/ think/ know

7. buys

8. is

9. rains/ is raining

10. is cooking/ cooks

11. is studying

12. watches

13. is coming/ don't want

14. is singing

15. do you read

16. rises/ is rising

17. heard/ know/ said

18. starts

19. are going/ Do you come

20. has

21. see/ are wearing

22. buys

23. is eating

24. are riding

25. go

I.

1. went

2. drove

3. arrived/ was

4. asked/ had

5. said

6. told

7. walked

8. saw

9. stopped/ bought

10. was

11. didn't go

12. Did...get