5, 6, 5, 5, 5, 6
____how to solve the problem. [ ]
A. Only he knew
B. Only did he know
C. He only did know
D. Only did know he
业要加强现场监督检查,及时发现和查处违章指挥、违章作业和违反操作规程的行为。发现存在重大隐患;要立即停止供电;并向煤矿主要负责人报告。