Strong fencing at watering points can offer protection.

VOA: special.2010.07.27

So, if you were someone that was getting it after it had been passed through many people, you wouldn't have as strong or as lengthy a protection as the first individual did.

如果一个疫苗经过很多人的传递,再接种到你身上,你不会获得像第一个接受疫苗的人,那样强效持久的免疫效果

耶鲁公开课 - 生物医学工程探索课程节选

Medical science, bolstered by research from the U.S.Environmental Protection Agency, shows a strong link between air pollution and heart disease and stroke.

VOA: standard.2010.08.04

He says the difference is that the BlackBerry's reputation is based on its strong data protection.

VOA: standard.2010.08.02