像其它行星一样，火星不是十分圆的，由于自转，两极稍偏。

Like other planets, Mars is not perfectly round; it is flattened at the poles because of its spin.

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威尼斯议会最终允许圆型船进入原本只供商船使用的贸易，从而降低了三分之一的运输成本。

The Venetian Council finally allowed round ships to enter the trade that was previously reserved for merchant galleys, thus reducing transport cost by one third.

youdao

让我们来做第二部分，这是单位圆上的一段圆弧。

Let's do the second part, which is a portion of the unit circle.

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During this part, when you're doing a quarter of a circle, this is supposed to be a quarter of a circle.

在这部分,当你沿着四分之一圆运动,这就是个一个圆的四分之一

耶鲁公开课 - 基础物理课程节选

So that a half circle, instead of calling it 180 degrees, And a quarter circle, instead of 90, It's good to know certain famous angles.

半圆,不说它是180°,四分之一圆,不叫90°,知道一些常用的角度很有必要

耶鲁公开课 - 基础物理课程节选