get to the bottom or root of a matter 刨根问底

“刨根问底”，汉语成语，意思是盘究查问，探究底细，弄清根底原由。可以翻译为“get to the bottom or root of a matter”，常用表达“对某事刨根问底（make detailed enquiries of something ）”。

例句：

他这个人就爱刨根问底。

He's never satisfied until he gets to the bottom of things.