have a finger in the pie
通晓一切
A:Where can I get the information, Kate?
A：凯特，我从哪儿能得到信息?
B:Ask John. He's sure to know about it.
B:问约翰吧。他一定知道。
A:Why?
A：为什么?
B:He has a finger in the pie.
B：他这人无所不知。