A.原材料的質(zhì)量 B.冷拔總壓縮率 C.冷拔的次數(shù) D.A與B
A.50% B.70% C.90% D.100%
A.分段開(kāi)挖,先挖后撐 B.分層開(kāi)挖,先挖后撐 C.分段開(kāi)挖,先撐后挖 D.分層開(kāi)挖,先撐后挖