In three-dimensions, it could even be a saddle point.
在三维空间中，它甚至可以是一个鞍点。
2
Some movements involving primarily vertical or horizontal motions of the body as a whole, in which rotations can be ignored, can be studied using simple equations of linear motion in threedimensions.
有些运动主要涉及整体的垂直或水平运动，其中转动可以忽略，可以用三维线性运动的简单方程来研究。
3
There are three states of matter, threedimensions. Triangulation is how we get our bearings.