Just to say a little bit about smallpox, because unlike chickenpox, which if you haven't had, you've probably seen a case of it.

我们稍微说一下天花,因为它不像水痘那样,就算你没得过你也见过

耶鲁公开课 - 生物医学工程探索课程节选

Right, now are there people here that have not had chickenpox, right?

好,现在这里的人,有人没得过水痘,是吧

耶鲁公开课 - 生物医学工程探索课程节选

Now, so there's probably a number of people in this room, so when I first started teaching this class 20 years ago, everybody in the room had had chickenpox.

现在,这间教室中的很多人也许,在二十年前,我第一次教这门课的时候,当时教室里的每个人都得过水痘

耶鲁公开课 - 生物医学工程探索课程节选