If you had five slaves and a good piece of land in Alabama in 1820, you might very likely have fifty slaves and a hell of a lot more land a decade later.

820年,如果你在阿拉巴马州,拥有五个奴隶和一块肥沃的土地,十年后你很可能就会拥有五十个奴隶,以及更多的土地

耶鲁公开课 - 美国内战与重建课程节选

Even if you imagine that slaves did the work, you would need a hell of a lot of them, over a long period of time, and you had to feed them, if nothing else.

哪怕你想象这个墓穴是由奴隶所建造,那也一定是成千上万的奴隶,经过了相当长的时间工作,至少,你还要养活这些奴隶

耶鲁公开课 - 古希腊历史简介课程节选