elbow grease

elbow grease意思是“用一点点功”，这个说法有什么典故或来源么？？

为什么在手臂和肘部涂抹上油脂，可以节省力气和加强效果？？？

elbow grease
elbow grease字面意思是肘部涂的油脂，引申为干活的力气，做事的技巧。

古时候，英国的工人们在给贵族家帮佣的时候，为了把窗子、家具和地板清扫干净并抛光打蜡，总是在手臂和肘部涂抹上油脂，以节省力气和加强效果。

后来人们就把elbow grease比喻为体力劳动，艰苦的工作，苦差事。

Elbow grease(费体力的工作，重活) is a metaphor for working hard at manual labour, as in "You need to use some elbow grease". It is a humourous reflection of the fact that some tasks can only be achieved by hard effort and human energy, contrasting with the idea that there should be some special oil, tool or chemical product to make the job easier.

elbow grease [英][ˈelbəu ɡri:s][美][ˈɛlˌbo ɡris] n. 费体力的工作，重活; 网络 重活; 干活的力气; 费体力的工作; 1 the only thing we can do's dig. we can't get a crane here, so it's elbow grease. we'll try here first. 我们唯一能做的只是挖掘。这里没有起重机，所以这是费体力的工作。首先，试试这里吧。