下述哪项不属于胎儿附属物( )。
A.胎盘B.子宫肌壁C.羊水D.脐带E.胎膜
参考答案:B
解析:[考点] 胎儿附属物的形成及其功能[重点等级] ★★
Do be quiet! I’m trying to hear what the speaker _________ .[ ]
A. is saying
B. says
C. said
D. has said
简述实验动物的维生素C缺乏症。