And the way I remember that is I put a little cross here, and then I make that the plus end.

我还记得要,在箭头尾部打个叉，然后让加法完结了。

麻省理工公开课 - 固态化学导论课程节选

So you can imagine that adds real excitement and energy to the class and puts a little bit pressure on the professors to make sure that we have something worth coming half way around the world for.

可以想象,为课堂带去的兴奋和活力,也给教授施加了压力，我们要确保,能传授值得绕半个地球赶来学习的知识。

哈佛公开课 - 幸福课课程节选