ostrołęki

In a sentence

• Byłem niedawno w Ostrołęce i podziwiałem jej zabytki.

  I was recently in Ostrołęka and admired its monuments.

  In this sentence, 'Ostrołęce' is used as a locative form of the noun 'Ostrołęka', which is the name of a city. The locative case is used after prepositions indicating place, such as 'w', meaning 'in'.

• Miasto Ostrołęki jest znane z kultury kurpiowskiej.

  The city of Ostrołęka is known for Kurpie culture.

  Here, 'Ostrołęki' is a possessive genitive form showing that the city belongs to Ostrołęka indirectly. It's referring to the city's association with its name.

• Kupuję mapę Ostrołęki, bo planuję wycieczkę.

  I am buying a map of Ostrołęka because I plan a trip.

  In this example, 'Ostrołęki' is in the genitive case, which is used to denote possession or association. It indicates that the map pertains to Ostrołęka.