单项选择题
A.槽钢 B.等边角钢 C.H型钢 D.工字钢
A.直径48.3mm,厚度为3.6mm B.直径58.3mm,厚度为3.6mm C.直径48.3mm,厚度为4.6mm D.直径58.3mm,厚度为4.6mm
A.100mm B.150mm C.200mm D.300mm