A.20 B.30 C.40 D.50
A.1:2 B.1:3 C.1:4 D.1:5
A.60% B.75% C.80% D.90%
A.热轧钢筋 B.冷拉钢筋 C.热处理钢筋 D.高强钢筋
A.加水 B.加冰 C.加强振捣 D.加水泥浆