zì xíng chē / de / lún zhóu / xū yào / dìng qī / jiā / rùn huá yóu / cái néng / bǎo chí / shùn chàng自行车的轮轴需要定期加润滑油,才能保持顺畅。The axle of a bicycle needs regular lubrication to keep it running smoothly.