Many people even kept track of Lois online, through a 24-hour-a-day camera feed on the Museum's web site.

VOA: standard.2010.07.30

So they kept track of country-by-country, when cases of smallpox occurred, and as it was eliminated from regions of the country, they then certified those regions to be smallpox free.

它跟踪调查了一个又一个国家,记录天花在这个国家中何时发生,又是何时清除的,并确证这个区域已经没有天花

耶鲁公开课 - 生物医学工程探索课程节选

They are kept track of very closely, but because there's still smallpox that exists on the planet, there is some concern that that could be obtained and used to develop a weapon.

并且科学家们仔细记录病毒的使用情况,但因为这星球上仍存在天花,就会有人担心,某些人会获得天花病毒,并将其制成武器

耶鲁公开课 - 生物医学工程探索课程节选

and he kept track.

并作了记录。

耶鲁公开课 - 公正课程节选

And he kept track of how many people he gave the vaccines to, and then he kept track of what would happen to those people when a smallpox infection occurred in their community.

他与接种过牛痘的人保持联系,关注当天花在这些人周围肆虐时,他们身上发生了什么

耶鲁公开课 - 生物医学工程探索课程节选