【题目】He wrote a letter ________ he explained what had happened in the accident.
A. thatB. which
C. whereD. what
在线课程【答案】C
【解析】
考查定语从句。句意：他写了一封信。在信里，他解释了事故中发生的事。分析句子结构可知，“_____ he explained what had happened in the accident”是定语从句，修饰a letter，关系词在从句中作地点状语，应用关系副词where引导该从句。C选项正确。