单项选择题
A.the exhaust valves B.the fuel valves C.indicator cocks D.the fuel pumps
In each cylinder cover is a large central opening for m...
单项选择题In each cylinder cover is a large central opening for mounting （）
A.the indicating cock B.the starting valve C.air inlet valve D.the exhaust valve
In an ordinary four-stroke engine the exhaust valves op...
单项选择题In an ordinary four-stroke engine the exhaust valves open （）
A.after TDC B.before TDC C.after BDC D.before BDC
In an ordinary diesel engine the fuel injection begins ...
单项选择题In an ordinary diesel engine the fuel injection begins （）
