But Galileo already managed to find examples where things would roll on for a very, very long time.

但伽利略已经成功找到了,物体可以运动很长很长时间的例子

耶鲁公开课 - 基础物理课程节选

So how many time do you think-- you all have a piece of paper in front you-- how many time do you think you need to roll over the piece of paper ? for the piece of paper to reach the moon?

你们认为需要折多少次-,你们面前都有一张纸-,你们认为需要将纸折叠多少次,才能碰到月亮？

哈佛公开课 - 幸福课课程节选