运转自如

jiā rù rùn huá yóu shǐ huó dòng bù fen yùn zhuǎn zì rú

加入润滑油使活动部分运转自如。

Apply a lubricant to keep the moving parts from binding.

zhè xiē shè bèi nián dài jiǔ le yǐ bù tài néng yùn zhuǎn zì rú le

这些设备年代久了，已不太能运转自如了。

The equipment behaved poorly after so many years service.