wéi / xiū / rén / yuán / qīng / lǐ / le / chú / fáng / qiáng / shàng / de / tōng / qì / kǒng / yǐ / bǎo / zhèng / kōng / qì / liú / tōng维修人员清理了厨房墙上的通气孔,以保证空气流通。The repair workers cleaned the air vent in the kitchen wall to ensure proper airflow.