胎儿与母体通过下列哪些组织在绒毛间进行物质交换()。
A.绒毛间质
B.毛细血管内皮细胞
C.合体滋养层基膜
D.毛细血管基膜
E.母体毛细血管壁
参考答案:A, B, C, D
根据句意及首字母(汉语)提示,补全单词。
1. The box is e ______. There is nothing in it.
2. My mother asked me to d______ what my new pen-pal was like.
3. Look! The f ______ are working in the fields.
4. Alice and Jim ______ (结婚) in church last week.
5. Be quiet, please. I have good news to ______ (宣布).
正常成年人安静时的肺通气/血流比值为
A.0.084
B.0.024
C.0.48
D.0.84
E.0.24