人并不是只有一个圆心的圆圈；他是一个有两个焦点的椭圆。

Man is not a circle with a single centre; he is an ellipse with a double focus.

youdao

这些弯曲的星迹有一个明显的圆心，这就是南天极，它位于画面左上方边缘外一点点的位置上。

At the apparent center of the curving trails, the South Celestial Pole lies just off the upper left edge.

youdao

可测量的位置参数有切削齿复合片的圆心坐标及负前角、侧偏角等。

Measurable parameters include the coordinates of the circle center of the cutter teeth compact and the compact's back rake Angle and side sway Angle.

youdao

When a particle moves in a circle, it has an acceleration towards the center of this size, v^2 over R.

当一个质点在圆周上运动时,它有一个指向圆心的加速度,v^2 / R

耶鲁公开课 - 基础物理课程节选