二尖瓣狭窄最常见的心律失常是
A．房室传导阻滞
B．室性期前收缩
C．心房颤动
D．心室颤动
E．阵发性室上性心动过速
参考答案：C
—Tommy, you can never let others know what I have told you today.
—Don’t worry. I will keep the ______.
A．secret
B．money
C．address
D．grade
先天性腹股沟斜疝的发病因素主要是
A．
B．腹壁强庋降低
C．腹壁缺损
D．腹膜鞘状突未闭
E．先天性腹横肌和腹内斜肌发育不全
