Ответ:
1. This is Jane’s bag.
2. This is my mum’s car.
3. These are the Browns’ houses.
4. This is my boss’s money.
5. This is our biology teachers’ equipment.
6. Is this Cindy’s house’s or the neighbouring house’s roof? / Is this the roof of the Cindy’s house or the neighbouring house?
7. These are my brother’s dogs’ collars.
8. These are Ann’s and John’s children from their previous marriages.
9. These are Sarah and Nigel’s farms.
10. These are skillful thieves’ tools.