单项选择题
A.fresh water B.sea water C.lubrication D.fuel oil
The period when both inlet valves and exhaust valves ar...
单项选择题The period when both inlet valves and exhaust valves are open is referred to as （）.
A.valve loop B.valve uniflow C.valve overlap D.valve grinding
The period of valve overlap is when （）.A.the inlet valv...
单项选择题The period of valve overlap is when （）.
A.the inlet valve is open B.the exhaust valve is open C.both valves are close D.both valves are open
The outside diameter of the pipe is （） the diameter of ...
单项选择题The outside diameter of the pipe is （） the diameter of the bore of the piston rod, the result being that an annular space formed between the piston rod and the pipe.
A.less than B.greater than C.equal to D.twice larger than
