Why do people become firemen, policemen, soldiers, freedom fighters, all activities that cannot be explained in terms of self-interest alone?

不可能只用拿工资的理由，就能完全解释为什么总有人愿意做,消防员，警察，军人和争取自由的斗士？

耶鲁公开课 - 政治哲学导论课程节选

Policemen, firemen, ambulance driver, all those sort of things.

比如警察、消防员、救护车司机，类似这些行业的人。

想获得骑士爵位 - SpeakingMax英语口语达人