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我们在1989年3月至6月,在5所城乡中小学,93个班,5638名学生中进行吸烟情况调查,结果分析如下: 1 吸烟率在调查统计的小学四年级至高中
From March to June 1989, we conducted a survey on smoking prevalence in five primary and secondary schools in urban and rural areas, 93 classes and 5,638 students. The results are as follows: 1 Smoking prevalence was found in the fourth grade to senior high school