变形虫的外形随着伪足的伸缩而变化，这种现象说明细胞膜的结构特点是具有[ ]
A．识别作用
B．选择透过性
C．保护性
D．一定的流动性
答案：D
净重栏应填（）。
A．220
B．18500
C．18000
D．不填
A 15-year-old female with a urinary tract infection is admitted to the facility. She tells the nurse she hopes she's pregnant. Which of the following would be the best response by the nurse
A．"Does your mother know about this"
B．"Tell me what pregnancy would mean to you. "
C．"Congratulations. Does the baby's father know"
D．"I hope you aren't pregnant; you're too young. "
