only one state has mandatory PE classes for grades K thru 12,and according to some activists and edu

题目

only one state has mandatory PE classes for grades K thru 12,and according to some activists and educators,the lack of PE is one of the reasons so many American children struggle with obesity today.

答案

在美国只有一个州强制免费教育阶段的学生上体育课,根据一些活动家和教育家的看法,缺乏体育锻炼是现今许多美国儿童肥胖的原因之一.
“K–12”是指从幼儿园（Kindergarten,通常5-6岁）到十二年级（grade 12,通常17-18岁）,这两个年级是美国、澳大利亚及的免费教育头尾的两个年级.