单项选择题
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
Due to （） action of pistons some relative motion betwee...
单项选择题Due to （） action of pistons some relative motion between parts in contact in the coolant supply and return system must occur.
A.reciprocating B.rotating C.running D.removing
