有一隻雞和一頭豬一道旅行，走了很久都餓了。眼尖的雞看到附近有一家餐館，到了門口一看招牌，寫著「今日特價：火腿蛋三明治！」

豬叫了起來：Hold it！
雞問：What's the matter?
豬說：All they want from you is a contribution. They are asking me for total commitment!  (他們只要你做貢獻 "contribution"，卻要我賣命 "commitment")

這是從 "世界公民文化中心" 電子報節錄這段 Commitment 和 contribution 的笑話，這英式幽默你看出笑點了嗎？雞生蛋，可以不停地生，起碼還活著，這叫 contribution；豬啊，做成了火腿，徹底犧牲，這叫 commitment。所以當你的老闆要你 commit 或給 commitment，想清楚一點！假如你只是想要 contribution。

more example

劍橋英英字典的解釋：

contribution: something that you do or give to help produce or achieve something together with other people, or to help make something successful 協助共同生產或完成一件事

commitment: when you are willing to give your time and energy to something that you believe in, or a promise or firm decision to do something 做出奉獻時間精力的承諾