knife-edge

柯林斯词典

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]
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]
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。