And while drivers and passengers alike in large motor homes are supposed to keep their seat belts fastened on the road, it's not uncommon to find someone in back reaching for cold refreshments, spreading maps out on a table - even taking a nap, fully reclined!

VOA: standard.2010.03.01

Valvular disease is not uncommon in the world; we'll talk about that a little bit.

心脏瓣膜疾病在世界上是一种常见的疾病,我们会讲到一些相关的内容

耶鲁公开课 - 生物医学工程探索课程节选