单项选择题
Which will cause the high pressure cutout to stop the compressor in a R-22 system?（）
A.Condenser leakage B.A shortage of liquid refrigerant C.Excessive frost on the evaporator D.Not enough condenser cooling water
单项选择题 Insufficient refrigerant in a refrigeration plant may result in （）.
单项选择题 Air that may enter a refrigeration plant tends to collect in the （）.
单项选择题 Moisture should be kept out of an R-12 system because it tends to cause （）.
