How many people know that three times a week physical exercise,30 minutes each time has the same effect ? as our most powerful psychiatric drugs?

多少人知道，每周三次,体育锻炼，每次三十分钟，与最强劲的精神药物,有同样的效果？

哈佛公开课 - 幸福课课程节选

So how many before five minutes ago had heard the name Goudsmit?

有多少人在五分钟之前听说过Goudsmit？

麻省理工公开课 - 化学原理课程节选