按钢筋在混凝土结构中的作用分类不包括（）。
A.受拉钢筋
B.受压钢筋
C.架立钢筋
D.圆钢
参考答案：D
It is over______ from Shijiazhuang to Beijing.[ ]
A. three hours’ drive
B. three hour’s drive
C. three hour’s drives
D. three hours drive
