"September is not my month."
Translation:Wrzesień to nie mój miesiąc.
Is it possible to write a negative sentence of this type with być? Normally, you'd use the genitive after a negated verb, but być takes the instrumental--how does all that work out in this case (if it does)?
The thing is, it's when a positive sentence takes Accusative, then it turns into Genitive when negated. So this is not the case here. Negated sentence with Instrumental will still be in Instrumental:
Wrzesień nie jest moim miesiącem.