Breakdown of Fotel stoi między kanapą a regałem.
a
and / whereas (contrast)
stać
to stand
fotel
armchair
między
between
Questions & Answers about Fotel stoi między kanapą a regałem.
Why do kanapa and regał change to kanapą and regałem?
This is because of the preposition między (between). When talking about a static location (where something currently is), między forces the following nouns into the Instrumental case. Feminine nouns like kanapa take the -ą ending, while masculine nouns like regał take -em.
Why does this sentence use a instead of i to mean 'and'?
When you want to say 'between X and Y' in Polish, the standard set phrase is między X a Y. While i is the usual word for 'and', Polish strongly prefers a in this specific structure to bridge the two boundaries.
Could I use jest (is) instead of stoi (stands) here?
You could use jest and be understood perfectly, but Polish prefers to describe exactly how an object is positioned. Furniture with a clear base or legs, like an armchair (fotel), 'stands' (stoi). If it were something flat on the floor, like a rug, you would say it 'lies' (leży).
Can I use pomiędzy instead of między in this sentence?
Yes, you can! Pomiędzy and między mean exactly the same thing ('between') when describing where something is located, and both require the Instrumental case. Między is simply shorter and more common in everyday speech.