. In 1989 an international law was passed to stop people _____ waste into the sea. A. to put B. putting C. not to put D. not putting 答案:B为了了解某校今年准备报考飞行员的学生的体重情况,将所得的数据整理后,画出了频率分布直方图(如图),已知图中从左到右的前3个小组的频率之比为1:2:3,第1小组的频数为6,则报考飞行员的学生人数是( )A.36B.40C.48D.50