"The girl lives in a castle."
Translation:Pigen bor på et slot.
Yes it is quite confusing. I don't know how to tell whether to use i or på in these types of sentences either.
Had the same issue, I think this might be a special case as in German you would also say "live on a castle" rather then "in the castle", however both would be correct. So I am not sure about this one.
I agree with the confusion over i versus på. Can someone explain when to use one versus the other?