Вместо точек вставьте одно из местоимений who, whom, whose, what, which:

1. ... will help me?
2. ... of you will help me?
3. ... of these girls is the youngest?
4. ... is your hat?
5. ... is your telephone number?
6. ... pencil is this, Peter's or Helen's?
7. ... are you drinking?
8. ... are you expecting?
9. ... understands this rule?
10. ... of you understands this rule?

1. who.
2. which.
3. which.
4. which.
5. what.
6. whose.
7. what.
8. who(m) (or: what).
9. who.
10. which.