To fly off the handle 大发脾气
BMX is an abbreviation for bicycle motocross - the X is used as a symbol for 'cross'. BMX bikes are especially tough for use on dirt tracks and jumps.
BMX 是 "bicycle motocross 小轮车"的缩写。字母 X 是单词 'cross' 的符号代表。小轮车在泥地赛道上和在做各种跳跃动作时特别难驾驭。
短语 fly off the handle 的意思是大发脾气，勃然大怒。
When I told Dad I had crashed his car again he flew off the handle.
Jane is trying to get to sleep, so if you wake her up she will fly off the handle.
短语 to get a handle on something 的意思是理解、掌握某事。
I don't like this new computer - I can't get a handle on the strange keyboard.