单项选择题
A.The unit is working properly B.The face mask is not sealed properly C.The air bottle needs to be refilled D.The air supply hose has a leak
A.corrosive B.class B poison C.oxidizer D.explosive
A.The cargo's temperature is colder than the dew point of the air in the space B.The cargo's temperature is warmer than the dew point of the air in the space C.The dew point of the air in the space is lower than the dew point of the outside air D.All of the above