题目

 The 11.11 Shopping Festival held by Taobao attracted thousands of online shoppers,      _____ a record of nearly 20 billion yuan within 24 hours.        A. to make               B. made                  C. making                      D. having made 答案：CB．   选修4-2：矩阵与变换（本小题满分10分）已知矩阵，向量，求向量，使得．