题目

 The Turners consider ____ a computer, which is commonly considered ____ a great help in our work and study. A. to buy; to be  B. buying; to be      C. to guy; being    D. buying; being 答案：B为了解某校九年级学生的体能情况，随机抽查了其中20名学生，测试了学生1分钟仰卧起坐的次数，并绘成如图所示的频数分布直方图，根据图示计算，仰卧起坐次数在25～30次的频率是    ．