So you need hundreds of millions of doses, at least, and you need a way to distribute that around the world, and you need a way to keep track of who got sick and who didn't after they got vaccinated.

至少需要上亿支的剂量,还得有办法将疫苗运送到世界各地,你还要一种方法进行跟踪,在接种疫苗之后谁得病了和谁没得病

耶鲁公开课 - 生物医学工程探索课程节选

It is important to keep going after you finish this course.

在完成这一课程后，进一步的学习非常重要。

It's important 课堂 - SpeakingMax英语口语达人