"And the second issue is that behind NATO they see the United States and U.S.power and they remain as convinced as in the past that it is in the U.S.

VOA: standard.2009.09.04

The second issue is that the gene vector, in this case the plasmid, has to be compatible with the cells that you're trying to express the gene in.

接下来的问题是如何选择合适的基因载体,在这里用到的,质粒,必须与要用来表达基因的,受体细胞匹配

耶鲁公开课 - 生物医学工程探索课程节选

The second issue,the second response is even more important.

第二点，更为重要的是。

哈佛公开课 - 幸福课课程节选

The second one--the second study illustrates this issue even more clearly.

第二个研究,更加清晰的对该问题进行了阐述

耶鲁公开课 - 心理学导论课程节选