chorion avillosum

例句：

1. 1. The researchersfound that the chorion avillosum plays a crucial role in thedevelopment of the embryo.
   研究人员发现，胚胎外层膜在胚胎发育中起着至关重要的作用。
2. 2. During the early stages of pregnancy,the chorion avillosumis responsible for protecting the developing fetusfrom external threats.
   在怀孕初期，胚胎外层膜负责保护正在发育的胎儿免受外部威胁。
3. 3. The chorion avillosum is also known as the"bag of cells" because it containsall the cells that will eventually form theembryo.
   胚胎外层膜也被称为“细胞袋”，因为它包含了最终形成胚胎的所有细胞。