It's not going to be a backscatter event if your ping-pong ball hits the frame or these strings, or the top part.

打到原子核了就是背散射,如果打到框上。

麻省理工公开课 - 化学原理课程节选

And then, on the top of 3, we get another example: "In other words we've got to get on the ball, darling, what I'm saying, otherwise it'll be fluctuating and lack of true knowledge or crystallization of our plans."

然后，在第三页上面，又有一个例子：,换句话说我们必须去这个舞会，亲爱的，我是说，不然就会变得波动又缺少真知识,或使我们的计划结晶化“

耶鲁公开课 - 1945年后的美国小说课程节选

You have a tube, a transparent--a tube--a hollow tube, and at the top of the tube you throw a ball through so it whips through the tube and it comes out.

用一根管子,一根透明中空的管子,从管子最上面,你丢进去一个小球,小球迅速穿过管子,飞出来

耶鲁公开课 - 心理学导论课程节选