11. on　　 12. on　　 13. of　　 14. against　　 15. of

1. with　　 2. through　　 3. from　　 4. by　　 5. of　　 6. under　　 7. without　　 8. to　　 9. in　　 10. at　　

15. He bought a book yesterday, the author ________ which is a teacher.

14. The desk ________ which Jack is leaning is John’s.

13. Ours is a beautiful school, ________ which we are proud.

12. Do you know the building ________ which is flying a red flag?

11. His bike ________ which he went to work was stolen last night.

10. The age _______ which children can go to school is seven.

9. I was surprised at the way ________ which he treated the old man.

8. In the dark street, there wasn’t a person ________ whom she could turn for help.