[单选题]将矿块划分为矿房与矿柱，逐步回采，先采矿房，形成的采空区一般先不做处理，这种采矿法要求围岩和矿石稳固。这种采矿法叫：（）

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• ●    A cabinet or pace containing the control or valve for the fixed firefighting ytem mut be（）.
• ●    某地下矿山，单个矿块的采准切割巷道总长度68米，采切巷道掘进时回采矿石( )，矿房矿柱回采矿石量，矿块回采矿石总量3456t，则采准系数为239m/kt，采准工作比重176%。
• ●    Logitic回归系数与优势比OR的关系为（）。
• ●    Mainly eat 3 or 4 partly cloudy to overcat occaional rain（）lowly outh moderate or good.
• ●    （）any cae or upected cae of quarantinable dieae，or any cae of eruptive dieae or any death be dicovered，the local quarantine officer mut be notified immediately．
• ●    Should any cae or upected cae of quarantinable dieae，or any cae of eruptive dieae or any death be dicovered，the local Quarantine Officer mut be（）immediately.
• ●    已知A=40；B=30；C=100；D=50，逻辑“与”运算符为and，“或”运算符为or，“非”运算符为not。计算表达式（A>B+20）or（B+60
• ●    Mater are（）olely reponible for all damage or accident of whatever kind reulting from the navigating or handling of their veel by day or by night.
• ●    If he i a common carrier，he i abolutely reponible to the owner of the good carried （）any lo or damage to them unle caued by an Act of God or the Queen’ enemie，or the inherent vice in the good themelve，or the negligence of the owner of the good，or a general average acrifice.
• ●    系统中雷达状态包括Unknown、Operational（or ON）、Failed（or OFF）、Detached。
• ●    Owner are to be reponible for lo of or damage to the good or delay in delivery of the good only in cae the lo，damage or delay ha been caued by the improper or negligent towage of the good．Thi mean that（）.
• ●    The carrier i liable for lo of or damage to the good or delay in delivery caued by fire，（）the claimant prove that the fire aroe from fault or neglect on the part of the carrier，hi ervant or agent.