dziecka

In a sentence

• To jest książka dziecka.

  This is the child's book.

  Here 'dziecka' is in its genitive form, used to indicate possession.

• Nie znalazłem dziecka w grupie.

  I didn't find the child in the group.

  Here 'dziecka' is in its genitive form, used after the verb 'znaleźć' (to find) in the negative.

• Ona się troszczy o dziecka.

  She cares for the child.

  Here 'dziecka' is in its accusative form, used after the preposition 'o' (about/for) to denote the object of care.