klapkach

In a sentence

• Byłam na plaży w klapkach.

  I was at the beach in flip-flops.

  Here 'klapkach' is the locative plural form of 'klapki' (flip-flops), used to specify the location of the subject's footwear while at the beach.

• Nie mogę znaleźć klapkach pod łóżkiem.

  I cannot find the flip-flops under the bed.

  Incorrect. Should be: 'Nie mogę znaleźć klapek pod łóżkiem.', genitive plural for 'klapki' (flip-flops). 'Klapkach' is improperly used in this context.

• Wróciliśmy do domu w mokrych klapkach.

  We returned home in wet flip-flops.

  In this sentence, 'klapkach' is used correctly as the locative plural form of 'klapki' (flip-flops), following the preposition 'w' which governs the locative case.