看绝望的主妇学英语：Knockoneself out

Knockoneself out：Feel free (to do something); or in other words, do something for as long and as much as you like. （想做就去做、怎么着都行）

中文释义：Knock oneself out：一般用于鼓动某人放开去做某事，相当于： I don’t mind, just do whatever you want ；还记得：At liberty to do sth吗？没错，如果某人对你说：”knock yourself out” 就表示：You’re at liberty to do it. 我允许你放心大胆去干，不要有任何顾虑，去你想做的，go for it！

注：如果是以 “Knock oneself out”其它人称形式出现，则表义大为不同，指因过度操劳、或全力以赴干事情而累倒、甚至是失去知觉。

E.G.：Listen, I promised Tom I wouldn’t knock myself out campaigning for this homeowners thing.

“Knock yourself out”，这类的表意一般是指鼓励某人放手干某事，口语中使用相当高频；“knock myself out”,或者“knock himself out”，用于书面语，表述某人的状态时，语义通常是指我绿色文字标注的部分。