环境问题词汇（pollution, recycle等） — 英语填空题
题目
根据句意和汉语提示填写单词，每空一词：At the school's Green Week, students learned that we should sort our ___ (垃圾) and ___ (回收利用) paper, glass and metal instead of throwing them away. Besides, planting more trees can help reduce air ___ (污染) in our city.