单项选择题
In a compression refrigeration plant the refrigerant is under low pressure in the （） and under high pressure in the （）.
A.compressor；condenser B.condenser；evaporator C.throttle valve；evaporator D.evaporator；condenser
单项选择题 A feeler or thermal bulb is used for the expansion valve to （）.
单项选择题 The expansion valve on a Freon system controls the （）.
单项选择题 During working, thermostatic expansion valve should be （）.
