So low-income kids before they even leave elementary school are years behind where they should be.

低收入孩子在离开小学前,已落后多年。

哈佛公开课 - 幸福课课程节选

or they would help, they would tutor elementary school- to high school- aged students,

也可以为他们的孩子辅导功课，从小学到高中都可以，

帮助多文化的家庭 - SpeakingMax英语口语达人

They did this in 1,800 elementary school children, so these are about eight year-olds.

于是科研人员给一千八百名,八岁左右的小学生分发疫苗

耶鲁公开课 - 生物医学工程探索课程节选

So, the two most elementary ideas you learn are what is the average velocity of an object, as then ordered by the symbol v-bar.

你们学过的两个最基本的概念是,物体的平均速度,用"v拔"表示

耶鲁公开课 - 基础物理课程节选