translation.en: Those stem cells are really important in the embryo when it develops, and they also sort of wake up if you have a fracture to help you with repairing the bone.
translation.zh: 这些干细胞在胚胎发育时期 有着非常重要的作用， 而且当你不慎骨折的时候， 它们会被激活以修复骨骼。