题目

 What great trouble we had _______ where his house was. A. in finding                 B. to find                    C. find                         D. found 答案：A将一个正方形沿对角线剪成两个完全相同的三角形，每个三角形面积都是9平方厘米，原来这个正方形的对角线长多少厘米？