get to the root of the matter

... 追奔逐北[ pursue and attack fleeing enemy] 追根究底[ get to the root of the matter] 追亡逐北[ pursue and attack] ...

刨的组... ... ◎ 刨分儿[ reduce] ◎ 刨根儿[ get to the root of the matter] ◎ 刨根问底[ inquire into the root of the matter] ...