据国内的医学统计，多见于女性的先心病为（）
A.主动脉窦动脉瘤
B.室间隔缺损
C.肺动脉瓣狭窄
D.房间隔缺损
E.动脉导管未闭
参考答案：D, E
They made no effort to hide their amusement ________ I produced a packet of sweets from my pocket.
A．however
B．whatever
C．whichever
D．whenever
与一般胶片不同，Χ射线胶片双面涂布感光乳剂层，其目的是为了增加感光速度和黑度。
