15.
A.
2. who (can't be omitted)
3. where (can't be omitted)
B.
1. whose (can't be omitted)
2. why (can be omitted)
3. that(can't be omitted)
4. when (can be omitted)
5. when (can be omitted)
C.
1. who ( can't be omitted)
2. that (can be omitted)
3. where (can't be omitted)
4. where (can't be omitted)
D.
1. when (can be omitted)
2. that (can be omitted)
3. who(can be omitted)
4. which (can't be omitted)
5. why ( can be omitted)
6. why (can't be omitted)
7. who(can't be omitted)
E.
1. who (can't be omitted)
2. whose ( can't be omitted)
3. that(can't be omitted)
4. where ( can't be omitted)
17.
2. where
3. whose
4. that
5. which
6. why
7. that
8. which
9. that
10.whose
