断路器偷跳的原因有哪些？应如何处理？
The purpose of the programmed purge cycle on an automatically fired auxiliary boiler is to（） ["cool the furnace to prevent pre-ignition","remove explosive vapors from the furnace","evaporate accumulated unburned fuel oil","provide sufficient air in the furnace to allow ignition of the fuel"]
钢材按成形方法分类（） ["锻钢","铸钢","热轧钢","冷拉钢"]
若电网发生工频谐振过电压时应如何处置？
新闻舆论导向的原则是（）。 ["真实性原则","党性原则","以正面宣传为主的原则","贴近大众原则"]
开关机构弹簧未储能，对开关分合闸有何影响？应如何处理？
