单项选择题 In an engine with a pot-shaped piston, some lubricating oil from the main bearing will pass along a （） in the crankshaft to the bottom end bearing andthen up a connection rod to the gudgeon pin.

单项选择题 In an engine with a pot-shaped piston, some lubricating oil from the main bearing will pass along a drilled passage in the crankshaft to the bottom end bearing and then up a connection rod to the （）.

单项选择题 In addition to lubricating, cylinder oil assists in forming a gas seal and contains （） which clean the cylinder liner.