—What do you think of being a volunteer John?—I find it a stressful job but one you can

问题补充：

—What do you think of being a volunteer, John?

—I find it a stressful job but one you can really help people.

A. where

B. which

C. when

D. that

答案：

(答案→)A. where

B. which

C. when

D. that

解析：考查定语从句。one指代job，即，先行词是job（工作），定语从句you can really help people不缺少成分，排除B、D；where指地点，也可指抽象的地点，当先行词是position，point，job等且从句不缺成分时，用where引导定语从句，意为“在（志愿者）这份工作中”。而when指时间，排除C。故选A。