小麻雀叽叽和喳喳飞到一家工厂的屋顶上,他们围着粗粗的大烟囱兜着圈子,玩得真快乐! 这时,一只小燕子飞来了,她尖声尖气地叫着:“喂,你们怎么在这儿玩呀?这个工厂排放的废气有毒。快离开吧!”说着,小燕子带着叽叽、喳喳离开了大烟囱,飞到不远处的一片绿阴丛中。“你们看,这儿种了银杏、刺槐、棕榈、法国梧桐……它们都能吸收废气,使空气新鲜。”小燕子又指着一株紫花苜蓿说:“这紫花苜蓿还能够报警呢!瞧,它的叶片上出现了白斑,说明这儿的 The little sparrows twitter and twitter fly to the roof of a factory, and they circle around the thick chimney and have fun! At this moment, a little swallow comes and she screams sharply “Hey, how do you play here? The exhaust gas from this factory is poisonous. Leave it!” Xiaoya swallowed the big chimney and flew far beyond the green shade. “You see, there are kinds of ginkgo, black locust, palm, sycamore ... they both absorb the exhaust gas and make the air fresh.” The swallow also pointed to a alfalfa and said: "This alfalfa can alarm! Look, Its leaves appear white, indicating here