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。
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 three dimensions.
旋转木马本质上是幻灯片导航，其中的内容垂直或水平旋转（因此得名“旋转木马”）。
Carousels are essentially slideshow navigations, in which the content rotates vertically or horizontally (hence the name "carousel").
人们喜欢看到垂直或水平的直线。
People like straight lines that are either vertical or horizontal.
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