单项选择题
A.fresh water B.vapor C.mixture D.liquid
The boiling and condensation points of a refrigerant de...
单项选择题The boiling and condensation points of a refrigerant depend on the （） exerted upon it.
A.temperature B.pressure C.velocity D.heat
Faulty operation of any system is indicated by very def...
单项选择题Faulty operation of any system is indicated by very definite （）.
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
