单项选择题
A.symptoms B.samples C.traces D.tracks
The refrigerating agent can （） at low temperature in th...
单项选择题The refrigerating agent can （） at low temperature in the evaporator.
A.expand B.evaporate C.condense D.distil
Because the expansion valve is just （） way open, the re...
单项选择题Because the expansion valve is just （） way open, the refrigerant is under low pressure in the evaporator.
A.little B.few C.a little D.a few
As the refrigerant passes through the valve orifice, it...
单项选择题As the refrigerant passes through the valve orifice, its pressure is reduced and part of the refrigerant turns into （）.
A.liquid B.oily mixture C.emulsion D.vapor
