、。
She tidied up the room before the guests arrived.
Literal
She [topic-は] guest [subject-が] not-come [during-うちに], room [object-を] tidied-up.
Two cleaning verbs to keep distinct: 掃除する is physical cleaning — sweeping, wiping, removing dust — while 整理する is more about organizing, sorting, putting things in order. You 掃除 a dirty room; you 整理 a cluttered desk. Both can apply to a room, but they suggest different states it was in: dirty versus disorganized. The ~ないうちに frame on 客が来ない expresses 'while [it] hasn't yet happened' — acting before the change occurs. Cleaning before guests arrive is a deeply ingrained Japanese host norm, where the state of the entryway and the visible spaces is read as a sign of respect.