单项选择题
A.C20 B.C25 C.C30 D.C35
A.三级,0.2mm B.三级,0.3mm C.三级,0.4mm D.二级,0.2mm
A.受弯构件及受扭构件 B.轴心受压构件及偏心受压构件 C.轴心受拉构件及偏心受拉构件 D.轴心受拉构件及小偏心受拉构件