单项选择题 Just after stopping the engine while the oil is still circulating.Check that uniform oil jets appear from all the oil outlet grooves in the crosshead bearing lower shell and the guide shoes.The oil flow from （） must be compared from unit; there should be a similarity in the flow patterns.

单项选择题 The cylinder oil is pumped into the cylinder (via non-return valves) when the piston rings pass the lubricating orifices during （）

单项选择题 If there are micro-seized areas on the liner or skirt scratch-over manually with a coarse carbo-rundum stone (grindstone), moving the grindstone （） at an angle of 20 to 30 degrees to horizontal.