One benefit of this change is that students will not fall victim to the "summer slide," or the well-documented phenomenon where students forget some of the knowledge they have acquired when too much time is taken off from school.
这一变化的一个好处是,学生不会成为“暑期滑坡”的受害者,或者说,不会成为那种有充分记载的现象的受害者,即当学生过多时间离开学校时,他们会忘记一些已学到的知识。
where 引导限制性定语从句,修饰先行词 phenomenon,在从句中充当地点状语(抽象地点)。从句无逗号与先行词分隔,且不可删去,符合限制性定语从句特征。从句内部包含定语从句 "they have acquired" 和状语从句 "when too much time is taken off from school"。