A terrible earthquake happened in that district at the end of 2004, many countries in the world paid close attention to this.
A. where
B. when
C. which
D. what
网友回答
A. where
(答案→)B. when
C. which
D. what
解析：
本题主要是对非限制性定语从句中关系词的考查。分析句子可知，关系词在此作定语，故排除选项D；根据句子结构，先行词在从句中作状语，从而排除选项C；根据句子的意思可知，先行词应该是at the end of 2004，而不是in that district，故本题的正确答案为B。