Breakdown of Lustro wisi między oknem a drzwiami.
okno
window
a
and / whereas (contrast)
drzwi
the door
między
between
Questions & Answers about Lustro wisi między oknem a drzwiami.
Why do okno and drzwi change to oknem and drzwiami in this sentence?
They are in the Instrumental case. The preposition między (between) requires the Instrumental case when describing a static location (where something is, rather than where it is going). Because the mirror just "hangs" (wisi) in a fixed spot, we use the Instrumental.
Why is the word a used for "and" here instead of i?
In Polish, when you say something is "between X and Y", you almost always use the set structure między X a Y. Using i here wouldn't be completely wrong, but a is the natural, traditional choice when establishing boundaries between two points in space.
Why does drzwiami have the plural Instrumental ending (-ami) if the translation says "door" (singular)?
In Polish, the word for door (drzwi) only exists in the plural form, even if you are talking about a single door. It is just like the English words "scissors" or "pants". Because it is a plural word, it must take a plural case ending.
Wait, why does oknem end in -em but drzwiami ends in -ami if they are both in the same case?