A.角钢 B.扁钢 C.圆钢 D.槽钢
A.2~4mm B.5~7mm C.8~10mm D.12~14mm
A.100~200mmB.100~300mmC.200~300mmD.300~400mm
A.1~2 B.2~4 C.3~4 D.3~5
A.A B.B C.C D.D