Three-dimensional space is defined by x, y, and z axes.

立体空间可用x，y，z描述。

X and Y position, but move along the Z axis.

X 和 Y 位置，但沿 Z 移动。

You'll sometimes see another one, k, which represents the z axis.

有看到另一个， k，代表 z 。

What about in three dimensions? Well, you add a 3rd axis called the Z axis, which is perpendicular to both the x and y axes.

在三维空间中呢 了第三个 叫做Z 它与x和y都垂直。

Or rather, I should say p orbitals, because we're talking about 3 dimensional space here, so there can be one on the x axis, and one on the y axis, and one on the z axis.

或者更确切地说， 我应该说 p 轨道，因为我们在这里谈论的是 3 维空间， 所以可以有一个在 x 上，一个在 y 上， 一个在 z 上。