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最佳答案：In the past few decades,our Earth has changed a lot,but to the bad direction.Amo
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最佳答案：Air pollution is the human introduction into the atmosphere of chemicals, partic
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最佳答案：空气污染(Air Pollution)We all know that clean air is important to good health. Where
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最佳答案：要多少字？Like Earth, other planets have sunlight, but the Earth is the only planet w
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最佳答案：There are many ways of traveling, People may travel by plane if they want to tra
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最佳答案：Henry was worried.This was his first time to go travelling by air.He did not kno
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最佳答案：Air PollutionThe United States produces more air pollutants than any other count
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最佳答案：At the present age,airplanes play a crucial role not only in our daily life but
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最佳答案：Electricity is very important nowadays,it give light to every family and make ma
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最佳答案：AirAir is all around us.It's around us as we walk and play.From the time we were