Ответ:
1. She is a relative of theirs.
2. He is a friend of hers.
3. We are former students of yours.
4. She is a niece of his.
5. I am a colleague of yours.
6.They are children of hers.
7.She is a neighbour of ours.
8.He is an ex-boss of hers
9.I am a student if his.
10.It is an office of hers.
Объяснение: