Well, for example,if our surface is a plane, a slanted plane given by some equation, ax by cz = d.

比如说，假如我们的曲面是一个平面，由公式ax+by+cz=d给出的，一个倾斜的平面。

youdao

Ok, three unknowns, but solving for aX+bY+cZ = d is too much to ask for in a swim drill metaphor.

三个未知因素，好比解三元方程，对一个游泳练习的比喻来说好像太过分了。

youdao

CZ – abbreviation for Control Zone.

管制区的缩写。

youdao