美 [ˈnʌkl daʊn]
努力工作：指认真努力地投入工作或学习。
knuckle down //
动词 to apply oneself diligently 开始努力做事
to knuckle down to some work
work very hard, like a slave
同义词： slave / break one's back / buckle down
开始认真工作
knuckle molding折角线缘材;折角饰材 knuckle down屈服;开始认真工作 n.
knuckle molding折角线缘材;折角饰材 knuckle down屈服;开始认真工作 n.
... muster 激起（某种感情） knuckle down 开始努力工作 temptation bundling 诱惑捆绑（把一件需要做但枯燥的事情和一件有趣的事情连在一起做，合二为一） ...
屈服；开始认真工作
I'm going to have to knuckle down to some serious study.
我得开始认认真真地学习了。
He would not knuckle down under their pressure.
他不会在他们的压力下屈服的。
You 'll really have to knuckle down if you want to pass the examination.
如果想通过考试，你确实应专心学习。
How long does it take me to find the k'th element? Linear. Because I've got to walk my way down it. OK? So in this case, you have linear access. Oh fudge knuckle.
线性的！因为我得从头,向下走一步步走,所以这里是线性访问，哦，有问题了吧。
计算机科学及编程导论课程节选 : 麻省理工公开课
"I think I knuckle down and focus a lot better when conditions are tough, " Webb said.
You've got to know when to have fun, but also knuckle down and do the hard work.
We've got to knuckle down, work hard and keep working at the shape.