1. We know their telephone number, but they don't know ours.
2. My car wasn't as expensive as hers.
3. A: How are your children?
B: Fine, thanks. How are yours?
4. Maria has got her suitcase, but her friends haven't got theirs.
5. Our flat isn't as big as theirs, but ours is much more comfortable.
6. Have you seen my coat?