单项选择题
A.Height of the machine
B.Temperature of the liquid seal
C.Gravity disc
D.Bowl diameter
单项选择题 The compressor in an air-cooled condensing refrigeration system is short cycling on the high pressure cutout switch（）
单项选择题 A cargo hold has been determined to have a relative humidity of 80% and a dry bulb temperature of 80 ℃ and a dry bulb temperature of 85℃.When the hold is sealed and the dry bulb temperature decreases, the relative humidity in the space will （）
单项选择题 A purge recovery system is used in a centrifugal air conditioning or refrigeration system to （）