刨根問底 [－－问－]

Jyutping paau4 gan1 man6 dai2
Pinyin páo gēn wèn dǐ

Definitions (CC-CEDICT)
  1. to dig up roots and inquire at the base (idiom); to get to the bottom of sth
Definitions (粵典–words.hk)
  1. x
Definitions (Wiktionary)
  1. phrase, idiomatic
    to get to the bottom of something
Definitions (Kaifangcidian)
  1. （沒有對應漢語詞彙）