A.0.5m/s B.1.0m/s C.1.5m/s D.0.25m/s
A.1/2 B.1/3 C.2/3 D.1/4
A.瓦斯喷出 B.煤与瓦斯喷出 C.瓦斯积聚
A.5 B.7 C.10 D.15
A.3m B.4m C.5m D.6m
A.50 B.80 C.100 D.150