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
单项选择题 The crankcase can not be opened （）the parts have been cooled down.
单项选择题 The crank throws are displaced from （） to obtained the same number of degrees between the different crank throws.
单项选择题 The crank pin journal is provided with large bores for （）.
