11. They went to St. Petersburg in summer.
       Where did they go in summer?
       When did they go to St. Petersburg?
       Who went to St. Petersburg in summer?
 12. I'll listen to rock music at home.
       Who will listen to rock music at home?
       Where will you listen to rock music?
       What kind of music will you listen to?
 13. Mary is going to learn English.
       Who is going to learn English?
       What language is she going to learn? 
14. Sam and his girlfriend have come to stay with us this weekend.
       Who has come to stay with us this weekend?
       Where have Sam and his girlfriend come to stay? 
15. There were five students in the class.
      Where were there five students?
      How many students were there in the class? 
16. It usually takes me five minutes to get to the college.
      How long does it take you to get to the college? 
17. My father is forty-seven years old.
      Who is forty-seven years old?
      How old is your father? 
18. This magazine costs fifteen rubles.
       How much does this magazine cost?
       What costs fifteen rubles?
       What kind of magazine costs fifteen rubles? 
19. They collected stamps.
      What did they collect?
      Who collected stamps? 
20. We have been friends with Vlad for quite a long time.
      How long have you been friends with Vlad? 
21. It is raining.
      Is it raining?
22. She likes cooking.
      Does she like cooking?
23. He has taken a few pictures.
      Has he taken a few pics?
24. They don't know English.
      Do they know English?
25. We didn't go to a disco yesterday.  
      Did you go to the disco yesterday? 
26. She was my great friend.
      Was she your great friend?
27. Mike collected posters last year.  
      Did Mike collect posters last year?