司机在站正常情况下凭（）显示关门，凭推荐速度码释放后以及进路防护信号开放.
参考答案：DTI
Have you got any particular plans for the coming holiday?
Yes._______, I’m going to visit some homes for the old in the city.
A．If ever
B．If busy
C．If anything
D．If possible
与X线量无关的因素是
A．管电流 B．管电压C．给予X线管的电能D．靶物质的原子序数E．X线管阳极、阴极间的距离
