环保组织的志愿者们在社区挨家挨户宣传垃圾分类的重要性。

The environmental group's ___canvassers went door-to-door to promote the importance of waste sorting.

志愿者们作为调查员挨家挨户收集居民对社区改造的意见。

Volunteers worked as ___canvassers, going door-to-door to gather residents' opinions on the neighborhood renovation.