know something inside and out
对某事非常熟悉，了解其内外
口语·表达精通某事
英文释义
to be extremely knowledgeable or familiar with something, to know every aspect or detail of it
例句
After years of practice, she knows the piano inside and out.
典故来源
源于物理空间概念，比喻对某物从内部到外部都熟悉，强调全面了解。