selectorn.挑选者；选择器selector installation选择器装置selector pen detector选择笔检测selector pen attention光笔注意信号selector potentiometer选择器电位计selector stepping magnet选择器步进磁铁Selector Engagement Zone选择器接合地带selector of fluorography荧光摄影选择selector carrying capacity选择器负荷容量selector release equipment选择器复位装置selector-pulse generator选择脉冲发生器