预告信号装置在电力系统发生不正常运行状态时,( )。
A. 警铃响,光字牌亮
B. 蜂鸣器响,光字牌亮
C. 警笛响,光字牌亮
D. 不一定
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220kV电压互感器的隔离开关作业时,应拉开二次熔断器,这是为了( )。
A. 防止熔断器熔断
B. 防止反充电
C. 防止二次接地
D. 防止短路
During the drafting of the Declaration of Independence and the draftingof the Constitution, the issue of Negro slavery was _____.
A. not raised
B. raised but voted down
C. bitterly debated
D. raised but because of strong southern opposition it was put asidefor greater objective
Slave labor was widespread in the south because______.
A. the cold weather in the north was not suitable for Negro slaves
B. Negro slaves could not cope with machines in factories in the north
C. Negro Slaves were best suited for the kind of plantation economy inthe south
D. the north world not allow slavery to spread into their states
One of the features of the early colonists which has strong influence onthe formation of American character is ___________.
A. religious intolerance
B. respect for personal success
C. stress on community harmony
D. None of the above
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