Near the Arctic Circle, it was the final part of the nation to be explored and settled.

VOA: special.2009.08.02

At any instant, your motion, if it follows any curve, locally can be approximated as being part of some circle.

在任何时候,如果做曲线运动,都可以近似地认为是圆周的一部分

耶鲁公开课 - 基础物理课程节选

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

These two cannons,however, were on a part of the ship that could turn in a complete circle.

VOA: special.2009.09.10

We know it's going around in a circle because if I find the length of this vector, which is the x-square part, plus the y-square part, I just get r square at all times, because sine square plus cosine square is one.

我们之所以知道它做圆周运动,是因为我求出了这个矢量的模长,也就是 x 的平方加上 y 的平方,我就得到了它在任意时刻的模长平方,因为正弦平方加余弦平方始终等于1

耶鲁公开课 - 基础物理课程节选

Some of the finest embassies are along the part of Embassy Row near Dupont Circle.

VOA: special.2009.09.21

(Speech) In an interview on French radio, Probst suggested the judge's order was part of a larger attack on the conservative circle surrounding Chirac.

VOA: standard.2009.10.30