Recently our community has launched a campaign among all the residents we are called up

问题补充：

Recently our community has launched a campaign among all the residents , we are called upon to do our little but to prevent the worsening environment.

A. where

B. which

C. as

D. when

答案：

(答案→)A. where

B. which

C. as

D. when

解析：句意：最近我们的社区已经在所有的居民中发起了一项运动,我们被要求我尽我们的力量来防止环境恶化。这里使用了定语从句，先行词是a campaign，后面是非限制性定语从句，从句中不缺少主宾表，缺少的是地点状语，所以用where引导定语从句。选A。