单项选择题
The sensing line for the low pressure cutout switch to a refrigeration system is located （）.
A.in the chill box B.before the receiver C.on the suction side of the compressor D.on the discharge side of the compressor
单项选择题 Which of the following statements is true concerning any evaporator?（）
单项选择题 A knocking sound emitted from an unloaded air compressor is probably caused by （）.
单项选择题 The refrigeration system low pressure cutout switch is actuated by （）.
