单项选择题 If the sump（）were to rise this would indicate water leakage into the oil an d an investigation into the cause must be made.

单项选择题 If the needle valve in a fuel injection nozzle sticks open （）.

单项选择题 If the flame from combustion in the cylinder of a four-stroke engine past the piston into the space below, the accumulation of flammable mixture would be ignited, thus resulting in （）.