B.
1. The blouse is made ... cotton.
2. My sister goes ... the country ... summer.
3. His aunt looks ... the children.
4. Where is your son? – He is ... school.
5. I'll finish this work ... 5 o'clock.
6. My birthday is ... the 3d of June.
7. I go to ... bed ... 12 o'clock.
8. Don't take the book ... the shelf!
9. Will you come ... my place ... next week?
10. The businessmen will arrive ... a few days.
11. I quite agree ... you.
12. We are going ... a walk. It is not raining.
13. I like travelling ... train.
14. Don't tell anybody ... it.
15. Are you looking ... you bag? Here it is.
16. Bob says he has been ... Canada three times.