How successful was the cotton boom, how important was the cotton boom, what is the relationship between the spread of slavery, the spread of cotton, and power?

棉花业的兴盛是如何的成功,如何的重要,奴隶制的传播,与棉花业的兴盛,以及权利的扩散之间有什么关系

耶鲁公开课 - 美国内战与重建课程节选

If you're a guy, you will not graduate.

如果你是男生，你就毕不了业。

布朗的学生们 - SpeakingMax英语口语达人