I played Ping-Pong even when I didn't have anyoneto play Ping-Pong with.

VOA: standard.other

And again, you don't teach an animal to play Ping-Pong by waiting for it to play Ping-Pong and then rewarding it.

同样，你并不能通过等待动物打乒乓球,然后给其奖励,来使动物学会打乒乓球。

耶鲁公开课 - 心理学导论课程节选

Raise your hand if you don't if you don't have a ping-pong ball yet.

这样就可以算,背散射的概率了。

麻省理工公开课 - 化学原理课程节选