This class at the same time is about rigorous fun.

本课程同时是一种严格的乐趣。

哈佛公开课 - 幸福课课程节选

Along the same vein, " I think he should avoid saying at the end of each segment of the class, " Ultimately, you'll have to decide what to think for yourself."

重蹈覆辙“,我认为他该对课程每部分结束时避而不谈，最终，你将不得不决定如何看待自己“

耶鲁公开课 - 死亡课程节选