单项选择题
A.the cylinder cover B.the bottom of bed-plate C.the sump D.the crankcase door
For one or two types of engine, the piston and rod can ...
单项选择题For one or two types of engine, the piston and rod can be withdrawn downwards from the cylinder into the crankcase and then out through the （）.
A.cylinder casing B.cylinder bore C.crankcase door D.aperture in the cylinder block
For an ordinary modem marine four-stroke engine the inl...
单项选择题For an ordinary modem marine four-stroke engine the inlet valves close （）.
A.after TDC B.before TDC C.after BDC D.before BDC
For an ordinary four-stroke engine the inlet valves ope...
单项选择题For an ordinary four-stroke engine the inlet valves open （）
