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
Last year the number of students who graduated with a driving licence reached 200,000, a(n)
__________ of 40,000 per year. [ ]
A. average
B. number
C. amount
D. quantity
关于胎儿窘迫的病因哪项不正确:
A.母体因素
B.胎盘、脐带因素
C.胎膜早破
D.胎儿因素
E.难产处理不当