1. Have you ever been to London? - Yes- When did you visit it?
2. I haven't heard anything about Nikolay recently. 
3. What are you looking for? - My notes. I've left it here. 
4. The teacher has come. You may enter the class. 
5. Who took my book?
6. Have you already finished your course-paper? - Not yet, I'm writing it now. 
7. This year we red several English books. 
8. We have just seen our new dean. 
9. I've found interesting material for my paper. 
10. Has father already come? -No. 
11. Victor came home very late. 
12. She has lost the key and now she can't get into apartments. 
13. Have you sent my letter? Yes
14. Where did you get such pen?
15. What did they bring from South?
16. Who has put that document on my table?
17. Why haven't you done your homework? 
18. Hi Boris. I haven't seen yoy for ages. Where have you been?
19. Since when have you been knowing Belov?
20. I haven't seen Oleg since we graduated the school.