维修人员正在检查大楼的通风管道系统是否有泄漏。

The maintenance crew is checking the ___ducting system for leaks in the building.

空调系统的金属管道需要定期清洁以避免积尘。

The metal ___ducting in the air conditioning system needs regular cleaning to prevent dust buildup.

工人们正在安装通风系统，将新鲜空气通过管道输送到每个房间。

The workers are installing a ventilation system, ___ducting fresh air to every room.