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.
霍尔丹认为这些刀口动态不仅仅是由于复杂性造成的，同时，还会因为同质性。
This book was written before the recent knife-edge election in Ghana, a successful exercise in democracy, conducted in the most strained of circumstances.
此书著于近期加纳那场胜负悬于一线间的选举之前，这是一场在最为紧张的环境下进行的成功的民主实践。
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.
尽管前途险恶，通用汽车还是传达出了直白的警告：除非债权人接受这个计划，否则公司将宣布破产，并将公司交给法院瓜分。

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.