To help accomplish that, General McChrystal noted that the training unit for Afghan forces is now a NATO command, rather than being just an American responsibility.

VOA: standard.2009.12.03

We talk about cells as being kind of the fundamental unit of humans and other multi-cellular organisms.

我们某种意义上把细胞视为,人体和其它多细胞生物的基本单位

耶鲁公开课 - 生物医学工程探索课程节选