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I/
1. whose
2. that
3. that
4. which
5. which
6. who
7. which
8. whose
9. which
10. that
11. that
12. what
3. why
14. who
15. when
16. whose

Partb/
1. D which
2. A whose
3. D which
4. D who

5. B whose
6. D when
7. B which
8. C where
9. D when
10. B whom

II/
1. Brenda, whom I went on holiday with, is a friend.
2. This is Mr.Smith, whose son Bill plays in our team.
3. Her book, which became a best seller, was published last year.
4. This is the bank where we borrowed the money.
5. I told you about a person who is at the door.
6. Jack whose car had broken down had to take a bus. 
7. I lent you a book which was written by one of my friends.
8. Some boys who were arrested have been released.
9. Do you know a restaurant where we can have a good meal?
10. I don't remember the day when I left school.
11. This is the man whom I met in Paris.
12. I wanted the painting which you bought.
13. This is the chair which my parents gave to me.
14. She's the woman who telephoned the police.
15. He's the person who wanted to buy your house.
16. We threw out the computer which never worked properly.
17. Are you the man who won the first prize?
18. The man who was driving the car was badly injured.
19. The children who live in the next street broken the window.
20. That's the woman whom I was telling you about.