题目

 The most interesting thing ____ we should pay attention to is the first thing ____ I have said. A. which; that     B. that; which   C. which; which    D. that; that 答案：D20．如果一个几何体的三视图如图所示，正视图与侧视图是边长为2的正三角形、俯视图轮廓为正方形，（单位长度：cm），则此几何体的侧面积是（　　）A．.$2\sqrt{3}$cmB．.$4\sqrt{3}$cm2C．8 cm2D．12 cm2