题目

His letter was indeed confusing-time and time again I read it, still I couldn’t make _____ of it. A．explanation              B．meaning           C．guess              D．sense 答案：D如果圆锥的底面周长为20πcm，侧面展开后所得的扇形的圆心角是120°，则该圆锥的侧面积是    cm2（结果保留π）．