广播电视英语短句 第 314 课：运动量太少-6

The study appeared online this week in Pediatrics, the journal of the American Academy of Pediatrics. 这项研究于本周刊登在《小儿科》网络版，这是一份美国小儿科学会的杂志。

The researchers say larger class sizes are another possible reason for the increase in injuries. 研究员们也提到大规模的班级也是导致受伤事件增加的另一个原因。

Larger classes can mean less supervision. 大班级意味着较少的管理。

The National Association for Sport and Physical Education says twenty to thirty students in a P.E. class should be the limit. 全美运动与体育教育协会指出，一堂体育课的人数限定应为 20 —— 30 人。