Olhe so esses exemplos:
This is our car.
These are our cars.
This car is ours.
These car are ours.
His family is rich; hers is poor.
Susan went to her house; Mary and John went to theirs.
Como podemos saber quando usar os Pronomes possessivos com ^s^.... Isso esta me confundindo muito. Espero que alguem tenha uma explicaçao plausivel pra me ajudar, por que nao sei qdo e Pronome Adjetivo ou so Possessivo.
your - yours
his - his
her - hers
its - its
our - ours
your - yours
their - theirs

