Visitors can stay in different kinds of places in Yosemite Park.

VOA: special.2009.01.07

in spite of the fact that we take a variety of chemicals into our bodies in different ways and we have to do that to stay alive, but we have mechanisms to control this very well.

尽管事实是我们从不同途径,摄入各种化学物质以维持生存,但我们能够很好地控制它们在体内的总量

耶鲁公开课 - 生物医学工程探索课程节选