单项选择题
Thermal energy in transition is also referred to as （）.
A.heat B.power C.horsepower D.foot-pound
单项选择题 Noise in a refrigeration compressor can be caused by （）.
单项选择题 The air charge leaving an intercooler, or after-cooler of an air compressor can be expected to be （）.
单项选择题 Before starting a reciprocating, steam-driven pump that has been idle for a period of time, you should （）.
