African Union chief Jean Ping told those at the conference that the money is coming at an opportune time, because African growth was "totally compromised" by the global financial crisis.

VOA: standard.2009.11.08

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

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