—What do you think of teacher Bob?—I find it fun and challenging.It is a job you are doin

问题补充：

—What do you think of teacher，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

答案：

(答案→)A. where

B. which

C. when

D. that

解析：先行词a job在定语从句中作状语，故选where。