根据超声声像图,提示结构为()。
A.脐带
B.胎盘
C.胎儿躯干
D.胎儿臀部
E.子宫肌层
参考答案:B
句型转换。
1. She is my aunt.(改为一般疑问句,作否定回答)
— _____she _____aunt?
—_____
2. We are good friends. (改为一般疑问句,作肯定回答)
— _____ good _____?
— _____.
3. My uncle is a policeman. (改为否定句子)
My uncle _____a policeman.
4. They are my sisters. (改为单数句子)
_____ my_____.
5. That boy is my brother. (改为复数句子)
_____ our_____.
软件的______是指软件只允许被授权用户使用。
A.安全性
B.保密性
C.可用性
D.完备性