Lots of people in urban areas are now concerned about the quelity of the air they ___ (breath).

题目

Lots of people in urban areas are now concerned about the quelity of the air they ___ (breath).
括号中的词变为适当的形式填入空白处,略作说明,顺便翻译一下句子.

答案

填 breathe 呼吸 （动词）
现在城区的居民关心他们所呼吸的空气的质量.