Battery powered electric lights have replaced dangerous devices that were once used. Good lighting, like good ventilation, is one of the major safety factors in underground mining.是什么意思_Battery powered electric lights have replaced dangerous devices that were once used. Good lighting, like good ventilation, is one of the major safety factors in underground mining.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句