"He studies Greek philosophy in a secret room in the basement."

Translation: Han studerer gresk filosofi i et hemmelig rom i kjelleren.

[Stigjohan]

"[...] Dette hemmelige rommet kaller han Platons hule."

[turidbrox]

Er dette fra Sofies verden eller noe?

[MrsSMBurns]

I've given up trying understand when it's "i" and when it's "på"....

[AEuropeanSpectre]

I thought with rooms, you always use «på» as the preposition? Or is that only with a bedroom («på et soverom»)?

[Josh_Overlien]

<pre> I learned this from norsklærer Karense on YouTube: På is used for the smaller locations/subdivisions of something bigger. Rooms in a house generally fall into this category. I believe 'i' is used in this sentence because a basement is being further subdivided into a room within the basement, so if you were talking about the room within the basement, you would still use på. The basement as a whole is being talked about in reference to the smaller room within, so I believe that is why 'i' is used for basement when every other time you'd use på. I hope this makes sense. A native speaker can feel free to correct me if this isn't entirely accurate. </pre>

[Josh_Overlien]

I'm sorry, I looked at the sentence again and saw 'i' being used for the secret room within the basement. So I don't know why it's used for the room within a larger room.