Other cities became major ports or places of deportation, for the domestic slave trade.

另一些城市则成为了国内奴隶贸易的,主要港口和奴隶被驱逐出境的地区

耶鲁公开课 - 美国内战与重建课程节选

I mean, I think it's because it's a huge immigration port.

我认为，这是因为它是个移民港口城市。

移民者的都市 - SpeakingMax英语口语达人