单项选择题 One of the functions of ventilation is to （） the humidity of spaces containing sources of moisture, or to （） the temperature of spaces not mechanically cooled such as the engine room.

单项选择题 Air conditioning is the process of treating air to control （） its temperature, humidity, cleanliness and distribution to meet the comfort requirements of the occupants of the conditioned space.

单项选择题 （）, iea steam cooler, may be filled in the boiler system to control the superheated steam temperature.