If we looked in 1950, this is the incidence of paralytic, or the worst form of poliomyelitis in the U.S.

让我们回首一九五零年,这表示的是在美国因脊髓灰质炎,所致瘫痪的发生率

耶鲁公开课 - 生物医学工程探索课程节选

We'v e shown that learning optimism prevents depression and anxiety in children and adults, roughly halving their incidence over the next 2 years.

研究证实，乐观可帮助儿童和成人,预防抑郁和焦虑，使未来两年的发病率降低一半。

哈佛公开课 - 幸福课课程节选

You have to test it by giving the vaccine to a large population of people, and then watching and seeing if you've reduced the incidence of the disease.

这样的测试的做法只能是,给大量人群分发疫苗,接着观察和了解,这种疾病的发病率是否有所降低

耶鲁公开课 - 生物医学工程探索课程节选