这个故事发生在十九世纪四十年代的广东。

The story happened in Guangdong in the 1840s.

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这就是十九世纪四十年代至二十世纪初期中国人学习外国的情形。

That was how the Chinese tried to learn from foreign countries in the period from the 1840s to the beginning of the 20th century.

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不过这些圣诞传统仅仅是从十九世纪四十年代才开始的，而且来源于德国。

However, these Christmas traditions only date back to the 1840s, and are actually German in origin.

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Richmond, Virginia, for example, became a huge slave-trading center by the 1840s and 1850s.

比如里士满和弗吉尼亚,在十九世纪四十年代和五十年代,它们成为了巨大的奴隶贸易中心

耶鲁公开课 - 美国内战与重建课程节选

And so that's what was done in the 1940s.

这就是十九世纪四十年代完成的工作

耶鲁公开课 - 生物医学工程探索课程节选

The first is this era, of the 1820s, '30s, '40s and '50s, Antebellum America, exemplified most obviously by the anti-slavery movement, which is where we're going to get to as we leave today.

第一个时期,是十九世纪二十年代,三十年代,四十年代和五十年代,内战前的美国,废奴运动就是其典型,这是我们今天下课前要弄明白的

耶鲁公开课 - 美国内战与重建课程节选