单项选择题
When starting an engine, the compressed air enters the cylinder when the corresponding piston is in position of its（）
A.suction stroke B.compression stroke C.power stroke D.exhaust stroke
单项选择题 The starting air entering the cylinder begins when the piston（）
单项选择题 In the starting system, the automatic valve is controlled by（）, and the cylinder start valves are controlled by（）
单项选择题 A marine diesel engine is started by（）
