1.This is my friend. These are my/our friends
2.This is his case. These are his/their cases
3.This is her hat These are her/their hats
4.This isn't my passport. These aren't our passport
5.This isn't her handbag. These aren't her/their handbags
6.Is this your coat? Are these your coats?
7.Is her passport red? Are their passports red?
8.Is my coat smart? Are my/our coats smart?