问题详情：
Safety in school has been of great concern because of frequent reports about accidents _______ students got injured or killed while in school .
A. that B. when C. in which D. for which
【回答】
C考查定语从句的关系词。此处accident为先行词，其在定语从句中作状语，相当于in the accident。
知识点：定语从句
题型：选择题
