单项选择题
A.≤32mm B.≤52mm C.≤72mm
A.≥22mm B.≥38mm C.≥58mm
A.0.4m~0.6m B.0.8m~1.2m C.1.4m~1.8m
A.一排炮 B.1m巷道 C.1m3原岩
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