A negative face has an outward normal pointing in a direction opposite that of the positive x-axis.

负向的外法线指向与正x轴相反的方向。

youdao

For now, trust me that postTranslate() with a positive third parameter moves the camera along the z axis.

现在，您只要相信，带有第三个正数参数的 postTranslate() 可使摄像机沿 z 轴移动。

youdao

The x axis is positive in the right direction, while the y axis is positive in the downward direction (again, this is in contrast to its traditional upward direction).

x 轴在右边为正值，但是 y 轴在下方为正值（这与传统的上方为正值相反）。

youdao

The highest probability now is going to be along the x-axis, so that means we're going to have a positive wave function every place where x is positive.

概率最高的地方是沿着ｘ轴，这意味着只要在ｘ,大于零的地方波函数都是正的。

麻省理工公开课 - 化学原理课程节选