11. I have been walking 10 km so far.
12. We have been walking since 3p.m.
18. Have you seen the newspaper for today?
19. Have John leaved already?
20. Yes, he has leaved an hour ago.
21. Have you taken your breakfast?
22. Yes, i have taken it at 8 a.m.
23. Have you ever been in this city?
24. Yes, i have spent a month here, two years ago.
25. They have been working at this house for a year and they haven't finished it yet.