Question

英语问题，回答一下，谢谢大家

告诉我为什么选A，谢谢！Safety in schools has been of great concern because of frequent reports about accidents ___ students got injured or killed while in school.A. in which
B. for which
C. which
D. when

Answer 1

(Safety in schools has been of great concern because of )frequent reports about accidents ___ students got injured or killed( while in school.)

我用括号括起来的你可以不看了，都是起定语作用的，用来修饰的。
句子的主体部分就是：frequent reports about accidents ( ___ students got injured or killed ) （加括号的原因是，括号中的部分都是作为定语修饰accidents）
意思是，频发的关于学生（在事故中）受伤或死亡的报告，其实就是 students got injured or killed in accidents.

Answer 2

一个定语从句 学生们受伤或被杀，那是在哪里受伤的呢，应该是要用in which 或者 where 也可以，个人理解哈

Answer 3

它省略了，那个In是in reports的，因为which也是代指reports的，所以用In which

Answer 4

A，定语从句，修饰 accidents ，相当于in accidents