The verb forms of "mieć" (to have) and the majority of Polish words are followed by the close direct object which is expressed in Polish by accusative.
Nouns - singular forms
NOMINATIVE
ACCUSATIVE
masculine (animate)
To jest brat(This is a brother)
To jest wujek(This is an uncle)
To jest syn(This is a son)
Mam brata(I have a brother)
Mam wujka(I have an uncle)
Mam syna(I have a son)
masculine (inanimate)
To jest dom(This is a house)
Mam dom(I have a house)
feminine
To jest siostra(This is a sister)
Mam siostrę(I have a sister)
neuter
To jest dziecko(This is a child)
Mam dziecko(I have a child)
Adjectives - singular forms
NOMINATIVE
ACCUSATIVE
masculine (animate)
To jest starszy brat (This is an older brother)
To jest miły wujek (This is a nice uncle)
Mam starszego brata (I have an older brother)
Mam miłego wujka (I have a nice uncle)
masculine (inanimate)
To jest duży dom (This is a big house)
Mam duży dom (I have a big house)
feminine
To jest młodsza siostra (This is a younger sister)