"La ragazza era arrivata nell'appartamento circa un anno fa."

[avellone42]

My translation (rejected): The girl had come to the apartment about a year ago.
The "correct" translation is not natural English - it would sort of stylistic, anyway. Being an English speaker, I don't know if this is the most natural way to express this idea in Italian (as opposed to using venire).

[oktaya]

It's weird either way. It sounds like someone came one year ago and never left the apartment again.

[oktaya]

And you're right I think because earlier levels offered "to come" when Arrivare was used.