题目

Joined by their friends, Troy and Gabriella staged a musical _______ their experiences, hopes and fears about the future. A. reflecting            B. reflected            C. being reflected       D. having reflected 答案：A 解析: 略小明要制作一个圆锥模型，其侧面是由一个半径为9cm，圆心角为240°的扇形纸板制成的，还需要一块圆形纸板做底面，那么这块圆形纸板的半径为    ▲    cm．