Questions & Answers about Umysł pracuje podczas snu.
Because podczas requires the genitive case, and the genitive singular of sen is snu.
- dictionary form: sen = sleep
- genitive singular: snu
So:
- podczas snu = during sleep
This is a very common pattern in Polish: some prepositions always force a certain case, and podczas is one of the prepositions that takes the genitive.
Umysł is in the nominative singular because it is the subject of the sentence.
In Umysł pracuje podczas snu:
- umysł = the subject
- pracuje = the verb
- podczas snu = a prepositional phrase telling you when
So umysł stays in its basic dictionary form here.