Because you see, also motivation and energy-- you don't need research for that, you know that when you are feeling good, you have more motivation, you have more energy-- of course, there is a lot of research to back that up.

因为动力和精力-,不需要研究就能明白，你知道感觉好时，动力和精力更充沛-,当然有很多研究支持这一点。

哈佛公开课 - 幸福课课程节选

The traditional answer is that These guys actually did press up against the rows in front of them And that this provided a momentum That gave the front line an advantage in beating the enemy facing them.

传统的回答是,他们实际上是在推挤前面几排友军,为其提供一种动力,使前线在与对面的敌人交战时具有优势

耶鲁公开课 - 古希腊历史简介课程节选