短语词组短语gas extraction hole 瓦斯抽放孔gas drilled hole 天然气钻井gas valve hole 气阀孔gas sampling hole 气体采样口;气体取样孔gas expansion hole 气胀孔gas firing hole 气眼gas escape hole 排气孔gas drainage hole 瓦斯抽放孔gas outlet hole 气体出口孔 返回 gas hole