Safety in school has been of great concern because of the frequent reports students got i

问题补充：

Safety in school has been of great concern because of the frequent reports students got injured or killed while in school.

A. where

B. when

C. which

D. that

答案：

A. where

B. when

C. which

(答案→)D. that

解析：同位语从句that只起连接作用不做成分。由于频繁的报道学生在校受伤或被杀，学校安全受到人们的关注。选D