"And again it's relevant to the entire community." A growing number of large American companies are finding that health care costs for smokers are higher than for non-smokers.

VOA: standard.2010.02.18

We'll think about it in section, how you don't need to vaccinate everybody, but you just need to vaccinate a critical number in order to stop the disease from progressing through a community.

我们在讨论会上讲这个,为什么不需要给每个人都接种,但你只需要让接种人数达到一个临界值,就能阻止这个疾病在社会中传播

耶鲁公开课 - 生物医学工程探索课程节选

Head of the International Red Cross Federation's Influenza team, Robert Kaufman, says the impact of a novel virus on a community without immunity is not just about the number of illnesses and deaths.

VOA: standard.2009.09.04

about the health of Kim Jong Il. The North Korean leader remained out of sight for a number of significant occasions, including the launch of a long-range rocket that angered the international community.

VOA: standard.2009.12.30

"When you really look deeper at what the AU is doing and what is happening at the regional economic community level, though the progress has not been what we might have expected a number of years ago, it has changed, and it is a work in progress, and next year this time we might be talking about the next summit within a very different context if we are looking at the political leadership of the day,".

VOA: standard.2009.07.02