There are still some active smallpox virus specimens kept in the world, and there are two sources of small--two places where smallpox is stored now.

世界上仍有地方保存着,一些具有活性的天花病毒样本,有两个地方还储存着天花病毒样本

耶鲁公开课 - 生物医学工程探索课程节选

So some parents now are choosing to save the cord blood, have it frozen, locked away somewhere just in case its useful to their child later in life.

一些父母现在选择保存脐带血,冷冻储存起来,保存在某个地方以防万一,也许孩子将来用得着

耶鲁公开课 - 生物医学工程探索课程节选