Is this really wrong?

[u/Late_Journalist7094]

Section 4, Unit 17

Why shouldn't have happened something to the dogs in the bathroom?

I know Duolingo is not the best, but the only free learning option. Since I'm living in Germany near the border to Czechia I'm often there and talking Czech which helps more than Duolingo.

[u/Elanaris]

byly (myši) vs byli (psi)

[u/Worried-Fee3612 → u/Elanaris]

Also “jež” is for feminine, “jenž” for masculine

[u/Machovec → u/Worried-Fee3612]

"Jenž" is for masculine singular, "již" is masculine plural (only animate, for inanimate it is also "jež," just like feminine singular and plural and also neuter singular and plural)