Choose the correct words

1. This is [Marcella's|Marcella] mobile phone.
2. Is this notebook [your|yours]?
3. [Who's|Whose] rollerblades are these?
4. This is the [car's key|key of the car].
5. [Who|Who's] that man? That's my teacher.
6. This is [Nick's and Mary|Nick and Mary's] house.
7. [Hers|Her] birthday is in May.
8. Those are the [children's|childrens'] grandparents.
9. These bikes are [their|theirs].
10. Where are the [boys'|boys] jackets?
11. What is the [address of the house|house's address]?