knife-edge testing刀形测量;刀形丈量
knife-edge interferometer刃型干涉仪
knife-edge armature刃口式衔铁
Knife-Edge Crossing刀锋式飞越
knife-edge gearing刀缘支承
knife-edge pulse偃刀脉
double knife-edge双刃
Foucault knife-edge傅科刀口
knife-edge methods刀口检测法
PHRASE（习语） 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。
ADJ（形容词） 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。