单项选择题
A.symptoms
B.samples
C.traces
D.tracks
单项选择题 The refrigerating agent can () at low temperature in the evaporator.
单项选择题 Because the expansion valve is just () way open, the refrigerant is under low pressure in the evaporator.
单项选择题 As the refrigerant passes through the valve orifice, its pressure is reduced and part of the refrigerant turns into ().