单项选择题
A.passing it through the expansion valve
B.condensing refrigerant in the system condenser
C.passing the gaseous refrigerant through the heat interchanger on the suction side of the compressor
D.maintaining a high pressure on the systems receiver
单项选择题 In a refrigeration system, the refrigerant absorbs the latent heat of vaporization in the（）.
单项选择题 The FIRST thing to do to ensure that a refrigeration unit will not start while undergoing repairs, is to （）.
单项选择题 One of the main differences between the various types of screw pumps is in the （）.