fetal sac

• 胎囊

fetal sac的用法和样例：

例句

1. It involves removing a small amount of tissue called the chorionic villi, which is located on the outside of the fetal gestational sac and will later become the placenta.
   该检验将少量位于胚胎胎囊外部叫做绒毛膜绒毛的组织移除，该组织未来将成长为胎盘。