knife-edge

基本解释

Mr Haldane has suggested that these knife-edge dynamics were caused not only by complexity but also—paradoxically—by homogeneity.
霍爾丹認爲這些刀口動態不僅僅是由於複襍性造成的，同時，還會因爲同質性。
This book was written before the recent knife-edge election in Ghana, a successful exercise in democracy, conducted in the most strained of circumstances.
此書著於近期加納那場勝負懸於一線間的選擧之前，這是一場在最爲緊張的環境下進行的成功的民主實踐。
With its future on a knife-edge, GM delivered a blunt warning that unless its creditors accepted the plan, it would declare bankruptcy and leave the courts to carve up the company.
盡琯前途險惡，通用汽車還是傳達出了直白的警告：除非債權人接受這個計劃，否則公司將宣佈破産，竝將公司交給法院瓜分。

The risk of contagion is ever-present: Spain is in worse shape than before, Italy is on a knife-edge.
ECONOMIST: Charlemagne
Until the 1997 general election, this seat was on a knife-edge between the Tories and the Liberal Democrats.
ECONOMIST: Through the looking glass
In his frenzied business, where customer loyalty can turn on a knife-edge, you've got to keep selling, selling, selling.
FORBES: Sell the Sizzle

To be on a knife-edge means to be in a situation in which nobody knows what is going to happen next, or in which one thing is just as likely to happen as another.
You can use knife-edge to refer to something that is very exciting or tense because you do not know what is going to happen next.