11. A. Because I liked pop music very much. 

B. Because I missed the early bus.

C. Because it was terrible.

12. A. Well done! B. The same to you. C. Thank you, sir.

13. A. Sure. B. What a good idea! C. Nothing much.

14. A. Yes, we are. B. Yes, they did. C. Thank you!

15. A. Yes, I have. B. Twice. C. For two years.