﹣2³+（﹣2×3）的结果是（　　）

    I like school days. I can learn many things from school. We have four classes in the morning and two in the afternoon. I like weekends, too. We don't go to school on Saturdays and Sundays. I often play ping-pong and play basketball on Saturday morning. I often play the violin (小提琴) on Saturday afternoon. I often do homework and play football on Sunday morning. I often go to the park on Sunday afternoon.

  ①为了了解全校学生对任课教师的教学意见，学校向全校学生进行问卷调查；

  ②为了了解初中生上网情况，某市团委对10所初中学校的部分学生进行调查；

  ③某班学生拟组织一次春游活动，为了确定春游的地点，向全班同学进行调查；

  ④为了了解全班同学的作业完成情况，对学号为奇数的学生进行调查．