Ответ:
а)
1.my
2.Their
3.your
4.His
5.Our
6.Her
7.its
8.my
b)
1.This is Angela's brother.
2.This is Antonio's book.
3.Ann is Mark's mother.
4.They're Sara's children.
5.My brother car is Fiat
6.Jim is Sally's boyfriend.
7.This is Tim's pen.
8. They're my sister's keys.