1. It's our duty to save wate
　　2. As we know , water is very important to man,
　　3. we can't live without water.
　　4. The amount of water which is suitable to drink is less and less.
　　5. But some people don't care about it .
　　6. Many rivers and lakes are seriously polluted.
　　Something must be done to stop the pollution.
　　7. It"s our duty to protect our environment。
　　8. It is very important to take care of our environment
　　9. We should not throw litter onto the ground
　　10. We should not spit in a public place/ cut down the trees
　　11. We should plant more flowers and trees。
　　12. We must pick up some rubbish and throw it into a dustbin
　　13. If everyone makes contribution to protecting the environment, the world
will become much more beautiful.
　　14.Trees are very helpful and important for us.
　　15.We should plant more and more trees in order to live better and more healthy
in the future.
　　It's everyone's duty to love and protect the environment.

• amount [ə´maunt] n.总数；数量 v.合计 (初中英语单词)
• suitable [´su:təbəl, ´sju:-] a.合适的，适当的 (初中英语单词)
• seriously [´siəriəsli] ad.严肃；严重，重大 (初中英语单词)
• everyone [´evriwʌn] pron.=everybody 每人 (初中英语单词)
• litter [´litə] n.杂乱 v.乱丢 (高中英语单词)
• contribution [,kɔntri´bju:ʃən] n.贡献；捐献；投稿 (高中英语单词)
• environment [in´vaiərənmənt] n.郊区；周围；条件 (高中英语单词)
• rubbish [´rʌbiʃ] n.垃圾；碎屑；废话 (英语四级单词)