打爛沙盤問到篤 [－烂－盘问－笃]

Jyutping daa2 laan6 saa1 pun4 man6 dou3 duk1
Pinyin dǎ làn shā pán wèn dào dǔ

Definitions (CC-CANTO)
  1. to investigate and find out everything; to keep asking many many questions; to ask many questions to try to get to the bottom of something