polski · B1 · grammar · 4 minutes
Relative clauses with który
Make który agree in gender/number with its antecedent and choose case from its role inside the relative clause.
Understand the choice
Relative case must be solved inside the smaller clause. Koleżanka is feminine and z requires instrumental, so z którą is correct regardless of the outer structure.
Core rule: Który forms decline like adjectives; antecedent gives gender/number, while the inner verb or preposition gives case.
Notice it in context
To koleżanka, z którą prowadzę projekt.
This is the colleague with whom I run the project.
Z którą agrees feminine and instrumental; prowadzę closes the relative information.
Mężczyzna, którego widziałeś, jest sąsiadem.
The man whom you saw is a neighbor.
Masculine animate direct object gives którego.
Książki, które leżą na stole, są moje.
The books that lie on the table are mine.
Non-masculine-personal plural subject gives które.
What to remember
- Co is common as an indeclinable relative in speech but który is clearer for case learning.
- Czyj expresses whose as a question/relative-like possessive.
Common trap: Do not copy the antecedent’s outer case.