单项选择题
A.fresh water
B.fresh air
C.salt water
D.artificial respiration
单项选择题 If liquid refrigerant accidentally comes in contact with the eyes, （） immediately.
单项选择题 （） is the circulation and refreshing of the air in a space without necessarily a change of temperature.
单项选择题 （） is the control of temperature and humidity in a space together with the circulation, filtering and refreshing of the air.