But in the United States today, child labor is not legal.

VOA: special.2010.08.01

Five things you learnt today, hand in your numbers and the legal forms and I'll see you on Monday.

今天我们学到了五个结论,别忘了把授权书和数字交上来,周一见

耶鲁公开课 - 博弈论课程节选