单项选择题
A.inwards B.outwards C.downwards D.upwards
During the inspection, the starting air valves should b...
单项选择题During the inspection, the starting air valves should be closed （） the engine from turning.
A.to increase B.to speed up C.to prevent D.to reduce
During repair,lubrication lines and orifices must be （）...
单项选择题During repair,lubrication lines and orifices must be （）.
A.taken away B.engaged C.connected D.sealed off
During （）, the starting air valves should be closed to ...
单项选择题During （）, the starting air valves should be closed to prevent the engine from turning.
A.overhaul B.running C.blowing down D.All of the above are correct
