词汇题,考察positive的意思。结合上下文语境:They talked about how helping other people transformed their experience of multiple sclerosis from something that victimized them to something that enabled them to be a positive force in the world. 这些人员讨论到,帮助别人可以帮助他们将自己很多僵化的经历,从让他们victimized他们到positive。所以a positive force 在语境里面需要和前面的victimize them构成反义词,victimize是有害的意思,所以选择beneficial。
A选项的confident 自信的,C选项的practical 实际的,C选项的specific 特别的,都不符合。
注:题目来源来自网络