分段绝缘器经常与（）配合使用，通过隔离开关的开合使独立区段停电或带电。
参考答案：隔离开关
Perce Blackborow and his companions stayed on Elephant Island for six months before rescue came, so they ________ a lot of difficulties.
A．must go through
B．may go through
C．must have gone through
D．could have gone through
中央液压系统1号ACMP受哪个电门控制？（）
A、P5板1号ACMP控制电门
B、P1板预留刹车和转弯控制电门
C、以上都是
