vertex|vertices

三角形的每个顶点都是由两条边相交形成的。

Each ___vertex of the triangle is formed by the intersection of two sides.

正方形的四个顶点位于其边角处。

A square has four ___vertices at its corners.

他的科学研究在获得诺贝尔奖时达到了顶点。

His scientific research reached its ___vertex when he won the Nobel Prize.