完成作文，说明大家保护环境的重要性并说明你的理由。
We live on the Earth．The Earth was ____ ，but now some parts are dirty．Let's work together to keep the Earth pretty and healthy because the Earth is only home for all the living things．We should ____．We should ____．We also need water and trees．So we shouldn't ____．We should stop ____．
