Daily Chinese Idiom Guessing Game
The person has gone, leaving the building empty. It describes a scene of loss and emptiness after someone's departure.
人已离去，楼中空空。比喻故地重游时睹物思人的感慨。
唐·崔颢《黄鹤楼》诗昔人已乘黄鹤去，此地空余黄鹤楼。”
After she moved abroad, her old apartment felt like a classic case of 'ren qu lou kong'.