A.預(yù)測(cè)預(yù)報(bào) B.有疑必探 C.先探后掘 D.先治后采
A.底板卸壓 B.頂板預(yù)裂 C.水力壓裂 D.深孔爆破
A.20h B.24h C.48h D.70% E.80%