A.5-10天 B.10-15天 C.15-20天 D.20-30天
A.6h B.12h C.24h D.48h
A.堅(jiān)硬巖;極破碎 B.較硬巖,破碎 C.軟巖,較破碎 D.較軟巖,較破碎