单项选择题
A.Distiller air ejector cooling medium
B.Saltwater heater discharge
C.First-stage internal feed box
D.Second-stage internal feed box
单项选择题 The component of a refrigerating system in which the refrigerant vaporizes and absorbs heat is known as the （）.
单项选择题 The low pressure side of a refrigeration system is considered to exist from the （）.
单项选择题 If the electric motor driving an air compressor fails to start, the cause may be a （）.