单项选择题
A.140m B.130m C.120m D.100m
A.15~20mm,1:3 B.15~25mm,1:3 C.15~20mm,1:2.5 D.15~25mm,1:2.5
A.构造钢筋 B.正弯矩钢筋 C.负弯矩钢筋 D.下部受力钢筋