题目

The leader in charge insisted that Qidong TV Station ________ a program to raise academic levels, which suggested that he ________ middle school students. A. should start, should care about               B. must start, should care about C. started, cared about                      D. start, cared about 答案：D以正方体的顶点为线段的端点，则这8个点可构成的异面直线的对数为（　　）A．150B．174C．198D．210