dì / yī / duì / kōng / qì / wū / rǎn / fēi / cháng / mǐn / gǎn / cháng / bèi / yòng / lái / jiān / cè / huán / jìng地衣对空气污染非常敏感,常被用来监测环境。Lichens are very sensitive to air pollution and are often used to monitor the environment.