At long intervals, he drew his thumb along the edge of his knife, and nodded his head with satisfaction.

每隔很长一段时间，他就用大拇指摸摸刀刃，满意地点点头。

youdao

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。

《柯林斯英汉双解大词典》

The edge of the knife is turned.

刀卷口了。

《新英汉大辞典》

The other a jagged line, like the edge of a steak knife.

BBC: How to buy jade in Asia

Using beams of electrons, he carved a cantilever out of the edge of each crystal (think of a knife held down on a table, with the blade sticking out).

ECONOMIST: Small-scale physics

Run a long, sharp knife around the edge of the cake and invert it onto a small rack, then invert it again onto a second rack so that the cake is right side up to complete cooling, 30 minutes more.

CNN: Food Central - Recipes - Incredible Melted Ice-Cream Cake