影响去游离的因素有（）
A.介质特性
B.热电子发射
C.冷却电弧
D.气体介质的压力
E.触头材料
F.阴极电压
参考答案：A, C, D, E
一侧肾结核合并对侧肾积水的发生机制是（）
A.输尿管口狭窄
B.输尿管口关闭不全
C.膀胱挛缩
D.输尿管下段狭窄
E.常常合并对侧肾结核
Current demographic trends, such as the fall in the birth rate, should favor ______ economic growth in the long run.
A．slow
B．quickened
C．speeded
D．accelerated
