单项选择题
A.two crankshaft revolutions in a two-stroke/cycle engine
B.two power strokes in a two-stroke/cycle engine
C.one power stroke in a two-stroke/cycle engine
D.two piston strokes in a two-stroke/cycle engine
单项选择题 If the main engine of an unattended engine room shuts down automatically, it will be indicated by an alarm （）.
单项选择题 White smoke exhausting from an operating diesel engine may indicate （）.
单项选择题 Electrically operated safety devices on auxiliary diesel engines function to stop the engine by （）.