在瑞典有一种叫做“学习圈”的组织。

In Sweden, they have a really cool system called Study Circles.

youdao

从远处看像一座巨大的拱门，它是一个连续的环，像一种方形面包圈。

Looking from a distance like a gigantic arch, it is a continuous loop, a kind of square doughnut.

youdao

大学城的学生可能还有另一种参与进阶数学的手段：数学圈。

Students in university towns may also have access to another lever for involvement in accelerated math: math circles.

youdao

One way is to say, if I do a full revolution, I think of the speed as a distance over time.

一种方法是,如果我转完整的一圈,我认为速度就是距离除以时间

耶鲁公开课 - 基础物理课程节选