一、问题提出在九年级数学第二轮专题复习的模拟考试中,遇到了这样一道选择题:题目:(2011年宁波市)把四张形状大小完全相同的小长方形卡片(如图1(1))不重叠地放在一个底面为长方形(长为m cm,宽为n cm)的盒子底部,如图1(2),盒子底面未被卡片覆盖的部分用阴影表示.则图1(2)中两块阴影部分的周长和是 First, the problem proposed In the ninth grade mathematics review of the second round of mock exams encountered such a multiple choice questions: Title: (Ningbo City, 2011) to four identical shape and size of the small rectangular card (Figure 1 (1 )) Are placed without overlapping on the bottom of a box with a rectangular bottom (m cm in length and n cm in width), as shown in Figure 1 (2), where the bottom of the box is not covered by a card. ) The two shaded parts of the perimeter and yes