The total amount of activity should be spread over at least three days throughout the week.

VOA: special.2010.06.08

Different amount of metabolic activity because one has a greater volume of cytoplasm than the other, for example, so these are exactly the right kinds of ideas.

大小不同,代谢活动的总量就会不同,可能因为一个细胞的胞质比另一个体积大,以上这些观点都是非常正确的

耶鲁公开课 - 生物医学工程探索课程节选

We've been working to make our schools healthier. We've been working to increase the amount of physical activity that our kids are getting, not just during the day at school but also at home.

VOA: special.2010.06.07

"Kids really get engaged in science in the garden where it's a kind of fun activity where they're collecting data and seeing how different temperatures will change the amount of water that's needed by a crop, so the science concepts come easily."

VOA: special.2011.06.14