There's a lot of interest in bone marrow and the stem cells that come from bone marrow and there's a couple of reasons for this.

人们对骨髓以及从骨髓中,提取的干细胞有着浓厚的兴趣,这其中有多种原因

耶鲁公开课 - 生物医学工程探索课程节选

But as the foreign slave trade was closed off, for a whole variety of reasons, only one of which was that there was this passage, sort of a vow, in the original Constitution that the question would be re-visited in 20 years, and 1808 was 20 years.

但随着海外奴隶交易,基于多种原因被封闭之后,这段只提到其中一个原因,是由于最初的宪法契约,这个问题要追溯到二十年前,内战开始前20年即1808年

耶鲁公开课 - 美国内战与重建课程节选