What's wrong with singular?
"Te tanulsz a nagy abalak mellett."
Not wrong. The better solution is: "A nagy ablak mellett tanulsz"
"At the window" sounds more everyday English to me. I guess it means "ablaknal" and that's what we wanted to say here, right?
I wrote "ablaknál" but duolingo said that is was wrong.
Can someone explain what is wrong with "Te tanultok a nagy ablak mellett."