"W lutym nie piszę książki."

Translation: I am not writing a book in February.

[Galois33]

If you wanted to have books in the above sentence, would it become
'W lutym nie piszę książek'?

[XanderStainton]

Can someone explain why we use the locative case here for February and how we use it? I don't think there is a lesson on locative posted. Thanks.

[Gerardd88]

The preposition "w" requires locative. It's quite logical when you think about - it indicates the location (in).

[Euhan1]

This is often true. Note that sometimes it takes accusative instead (but not with months).

[claudiuas]

What would be the plural of ksiaśżki (genitive case?)

[zagadka314]

Książki? książek.

http://aztekium.pl/przypadki.py

Try googling the endings you know and you'll notice one has way more results than the others. You can also check wikitionary:
https://en.wiktionary.org/wiki/ksi%C4%85%C5%BCka#Polish

[ankbhatnagar]

Why not ‘książkę’?

[Jellei]

"pisać" takes a direct object in Accusative ("piszę książkę"), but it's negated here. If you negate a verb that takes Accusative, it takes Genitive instead. Other cases stay unchanged when negated.

[zagadka314]

It sounds like "pisze" instead of "piszę," but it accepts "pisze" anyway.

[BrynSwiate]

Polish people usually pronounce an "ę" as an "e" if it's at the end of a word.

[Jellei]

And 'pisze' is accepted with a typo (as Duolingo allows one to not use Polish characters), not simply accepted.

[NieNieNieNie]

Indeed, my Polish teacher and everyone in YouTube Polish videos comments told me that pronouncing the final "ę" as a "ę" was a mistake.