---What do you think of teaching , Bob？
---I find it fun and challenging. It is a job you are doing something serious but interesting
A. where
B. which
C. when
D. that
网友回答
(答案→)A. where
B. which
C. when
D. that
解析：考查定语从句。本题定语从句的先行词是a job，后面定语从句的句子结构很完整，故使用关系副词where在句中做状语。BD项不能在句中做状语。C项的先行词必须是指时间的名词。句意：这是一份工作，在工作中你既可以做一些很严肃但是也很有趣的事情。故A正确。