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

Most of the people, and I think it's reasonable to guess that a very high majority of the people would be living on farms, engaged in farming, feeding themselves,and the rest of the community.

大部分人,我想有理由这样猜测,绝大多数人都在农场居住,在农场从事农业劳动,从而保证他们自己和整个社区的生存

耶鲁公开课 - 古希腊历史简介课程节选