巷道在水淹区下或老窑积水区下掘进时,巷道与水体之间的最小距离,不得小于巷道高度的()倍。 ["15","10","5"]
影响因素比较简单,目标比较明确的决策问题适用于() ["头脑风暴法","哥顿法","德尔菲法","名义群体法"]
根据《本地通信线路工程验收规范》7/2,6镀锌钢绞线公称截面积() ["30mm2<\/sup>","35mm2<\/sup>","37mm2<\/sup>","40mm2<\/sup>"]
严禁在水体下开采()煤层。 ["急倾斜","缓倾斜","倾斜"]
蹬地线
重心投影点