单项选择题
A.10 B.15 C.20 D.30
The crankcase cover should never be allowed to open for...
单项选择题The crankcase cover should never be allowed to open for investigation when （）
A.the engine stops B.the engine is running C.you repair the engine D.overhauling the engine
The crankcase can not be opened （）the parts have been c...
单项选择题The crankcase can not be opened （）the parts have been cooled down.
A.if B.as C.unless D.when
The crank throws are displaced from （） to obtained the ...
单项选择题The crank throws are displaced from （） to obtained the same number of degrees between the different crank throws.
A.one another B.the other C.each other D.each others
