Although interest in the World Expo has declined recently, many countries have made an extra effort to participate this year because China is the host.

VOA: standard.2010.05.02

If you are like me, too difficult about getting places on time, you have to make an extra effort the way I do, and arrive on time.

如果你们像我一样，容易迟到，你们就要像我一样努把力，要准时上课。

麻省理工公开课 - 电影哲学课程节选

At the margin, I'm reaping, I'm bearing the cost for the extra unit of effort I contribute, but I'm only reaping half of the induced profits of the firm, because of profit sharing.

从边际角度分析,我承担了多付出的全部边际成本,但我却只能得到一半的边际收益,因为利润是均分的

耶鲁公开课 - 博弈论课程节选