They spread through the air when the person coughs or sneezes or even sings and talks.

VOA: special.2009.03.25

One can stop spread of disease through a community without being 100% effective in each person who gets the vaccine.

疫苗能够遏制疾病在整个社区中传播,虽然对于每个人来说它并非百分之百有效

耶鲁公开课 - 生物医学工程探索课程节选

Anytime there's a risk that hits one person or one country the financial markets would spread it out over everybody and it gets very small.

如果有风险袭击一个人或者一个国家,金融市场就会将风险分摊到所有人身上,风险就变得微乎其微。

耶鲁公开课 - 金融市场课程节选

Information from the Framingham study showed earlier that happiness can spread from person to person.

VOA: special.2009.12.22

As we'll see in section today, a vaccine does not have to be totally perfect in order to prevent transmission of a disease, because when a disease enters a community its spread from one person to another.

有如我们今天看到的,疫苗不一定非要,绝对完美地阻止疾病的传播,因为当疾病侵入一个社区后,会在人群间传播

耶鲁公开课 - 生物医学工程探索课程节选

The idea is that if you spread risks they don't disappear, they're still there, but they're spread out over many people and the impact on any one person is reduced.

这种观念就是说如果你把风险分散...,风险仍然存在,并没有消失,但如果风险分散到许多人身上,那每一个人受到风险的冲击就会减少

耶鲁公开课 - 金融市场课程节选