Three-quarters of the world's AIDS deaths in 2007 were in sub-Saharan Africa where most health official recommend condoms as a way to prevent its spread.

VOA: standard.2009.03.22

That's one way of thinking why animal cells have cells from animals and humans have sub-cellular compartments.

这就不难想见,为什么动物细胞,包括,人类细胞有亚细胞结构区域了

耶鲁公开课 - 生物医学工程探索课程节选

So the allowed values for m sub l 0 are going to be negative l, all the way up to 0, l and then up to positive l.

所以m小标l的可能值,是从负l，一直到，然后到正。

麻省理工公开课 - 化学原理课程节选

Three-quarters of the world's AIDS deaths in 2007 were in sub-Saharan Africa where most health officials recommend condoms as a way to prevent its spread.

VOA: standard.2009.03.20