knife-edge (also knife edge)

• 1. 

  PHRASE 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. 形势难料; 扑朔迷离 [oft v-link PHR]

  例：

  The game is poised on a knife-edge. One mistake or one piece of good luck could decide it.

  比赛形势扑朔迷离。一个失误或是一点运气就有可能决定胜负。

• 2. 

  ADJ 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. 难以预料的 [ADJ n]

  例：

  Tonight's knife-edge vote could be uncomfortably close.

  今晚的投票难以预料，结果可能会很接近，真令人紧张。