单项选择题
A.80N/mm2B.90N/mm2C.100N/mm2D.110N/mm2
A.一类环境B.二类环境C.三类环境D.四类环境
A.箍筋和弯起钢筋B.纵筋和弯起钢筋C.弯起钢筋D.纵筋和箍筋