心室肌细胞动作电位O期形成的原因是（）。
A.Ca2+外流
B.Ca2+内流
C.Na+内流
D.K+外流
E.K+内流
参考答案：C
His first novel ________ good reviews since it came out last month.[ ]
A. receives
B. is receiving
C. will receive
D. has received
不孕症妇女了解有无排卵最简单的方法是
A．诊断性刮宫
B． * * 侧壁涂片
C．子宫颈黏液检查
D．激素水平测定
E．基础体温测定
