单项选择题
Badly leaking refrigeration compressor discharge valves will cause（）.
A.overfeeding of the expansion valve B.damage to the condenser C.constant running of the compressor D.flooding of the receiver
单项选择题 Mechanical energy in transition is referred to as （）.
单项选择题 If you change from a low pour point lubricant to a high pour point lubricant in a refrigeration system, （）.
单项选择题 When a vessel is in dry-dock, the vessel’s engineers should （）.
