煤与瓦斯突出按动力现象的成因和特征分为哪几种类型?
某上坡道长800m,坡度值为4‰,该坡道上有长400m,半径1400m的曲线,该段线路的换算坡度为()。 ["4‰","4.25‰","-3.75‰","-4‰"]
科技进步先进单位评选条件是:()。 ["A、领导重视","B、组织健全","C、承担局以上课题","D、科技投入逐年增加"]
包车时,软座车、软卧车、软硬卧车、硬卧车、软座硬卧合造车停留费按每日每辆()核收。 ["1002元","1200元","1500元","1800元"]
道岔区轨枕埋入式无砟轨道底座混凝土裂缝不得大于(),不得有竖向贯通裂缝。 ["0.1mm","0.2mm","0.3mm","0.4mm"]
压风自救系统应当达到什么要求?