Modifier + 室
室 (shì) is a noun meaning "room," "chamber," or "office." It designates an enclosed space used for a specific purpose. For example, 教室 means "classroom" and 办公室 means "office."
请大家回到教室,马上要上课了。
Qǐng dàjiā huí dào jiàoshì, mǎshàng yào shàngkè le.
Everyone, please return to the classroom; class is about to start.
他每天在办公室工作到很晚。
Tā měitiān zài bàngōngshì gōngzuò dào hěn wǎn.
He works in the office until very late every day.
医院的手术室正在消毒。
Yīyuàn de shǒushùshì zhèngzài xiāodú.
The hospital's operating room is being disinfected.