柔性防水材料有（）
A.聚合物防水砂浆
B.沥青防水卷材
C.合成高分子防水卷材
D.外加剂防水砂浆
E.外加剂防水混凝土
参考答案：B, C
The headmaster told the boy________the angry teacher, but he refused to. [ ]
A. to apologize
B. apologize to
C. to apologize for
D. to apologize to
当举高类消防车动作平台与曲臂间的夹角小于（）时，工作平台的左右回转被禁止。
A.55°
B.60°
C.65°
D.70°
