I/
1. The first boy who knows the truth has just moved.
2. I don’t remember the man whom you said you met at the canteen last week.
3. The only thing which make me worried is how to go home.
4. The man whose daughter is fond of dancing works for my father’s company.
II/
5. whose
6. who
7. which
III/
8. B
9. B
10. B