去年入冬以來，以北京為首的各大城市霧霾（haze）情況越來越嚴重，整個國家的空氣污染狀況令人擔憂．假如你是Li Hua，作為一個中學生，你對我國空氣污染的看法是什么呢？請分析空氣污染的現象、原因、應對措施，寫一份英文的倡議書，呼吁大家保護環境，減少對空氣的污染．
要點提示：
1．我國空氣污染的現象．（至少寫2點）
2．空氣污染產生的原因．（至少寫2點）
3．減少空氣污染的措施．（至少寫2點）
要求：
1.80詞左右，開頭和結尾已給出，不計入總詞數．
2．文中不能出現自己的姓名和所在學校的名稱．
Dear students，
As we all know，hazy days have been influencing our lives a lot in recent years．That warns us of the serious air pollution．

Big factories，power plants and cars all can cause air pollution．For example，chemicals in the smoke from power stations cause a lot of damage．Besides，the people's activities are also the sources of air pollution such as throwing the rubbish and smoking．What's more，the more trees are cut down，the less polluted air can absorb．Air pollution is becoming more and more serious，so we should take some measures such as planting more trees and stop factories from sending out waste air，what's more，we had better walk or take a bus．Protecting the environment is our duty．Everyone should play a part in saving the earth．（發出號召）

Big factories，power plants and cars all can cause air pollution．For example，chemicals in the smoke from power stations cause a lot of damage．Besides，the people's activities are also the sources of air pollution such as throwing the rubbish and smoking．What's more，the more trees are cut down，the less polluted air can absorb．Air pollution is becoming more and more serious，so we should take some measures such as planting more trees and stop factories from sending out waste air，what's more，we had better walk or take a bus．Protecting the environment is our duty．Everyone should play a part in saving the earth．（發出號召）

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