Then from 1820 to 1860, the forty years before the war, an estimated roughly two million American slaves were sold to satisfy the need of slave labor in the great cotton kingdom of the growing Southwest.

之后从1820年到1860年,这战争前的四十年间,据粗略统计有大约两百万美国奴隶被出售,以满足西南部,这个日益增长的棉业帝国对奴隶劳工的需求

耶鲁公开课 - 美国内战与重建课程节选

It's just, yeah, taking advantage of people who need a quick sandwich when they're at lunch and

这是利用了人们午餐时间需要快速来一份三明治的这个市场需求，

知道普雷特公司吗？ - SpeakingMax英语口语达人

Let me finish the picture here; here's my demand curve, here's my constant marginal cost at c, and I want to use this picture on the left now to figure out what the monopoly quantity is.

先把图画完,这条是需求曲线,这个是边际成本常量c,下面我们通过左边的图像,来找出垄断产量

耶鲁公开课 - 博弈论课程节选