一名推销员挨家挨户敲门，试图说服居民购买新产品。

A ___canvasser went door-to-door trying to convince residents to buy the new product.

政治运动的志愿者挨家挨户询问居民对候选人的看法。

Volunteers for the political campaign went door-to-door as ___canvassers to ask residents about their views on the candidate.