knock的相关短语
knock heads
knock heads 是美国的常用口语，敲打头部也就是在表达（粗暴地）管教，教训，也有在某些地方有争论，意见不合的意思。
The two of them knocked heads soon after they started working together.
他们俩刚开始一起工作就争论起来。
I am going in there and knock some heads if they don't start behaving.
如果他们不规矩的话，我就要过去教训教训他们。
