盘根问底

Explanation: Dial: careful questioning; Q: search ask. Cross-examination, held the root causes of things. 　　Source: Qing Li Ruzhen "Flowers in the Mirror" Forty-fourth back: "Although not as Lin Zhiyang overseas through several times, everything go does not pay attention, what is not widely seen and heard by hills inquisitive, today is also discussed, Also on tomorrow, all the belly of a number of stories, we see completed long time ago. "