One possible version：

Our school is our second home. It is our duty to keep it clean and tidy. Everyone can do something useful to improve the environment. First of all, I think it is necessary for us to clean the school yard every day. We must clean the windows and the doors. We also need to sweep the floor. Make sure everyone knows to throw rubbish into the dustbins. Those who do well in protecting the environment should be spoken highly of. Of course, a lot of trees and grass should be planted in our school so that our school looks greener. In a word, if every student makes a contribution to protecting the environment, our school will be much more beautiful.

题目分析：这是一篇给材料作文，介绍作为学生如何做好学校环境保护方面的工作。结合所给材料，可知本文主要考查一般现在时态，人称为第一，三人称，注意主谓一致问题，句子结构主要为系表结构，注意一些常见句式的应用，比如：It is our duty to......；Everyone can do......； I think it is necessary for us to......；We also need to……及 if every student......等句式的应用。写作中注意运用代词，注意多种句式交替运用。写作中注意叙述顺序，符合逻辑关系，注意要用题中所提示的单词和短语。

【亮点说明】本文结构紧凑，语言简练。开头介绍了保持学校环境的重要性，接下来介绍我们应该怎样做，最后说明只要人人去保护环境，学校将变得更加美丽。此处用了keep it clean， First of all, Make sure，throw rubbish into， spoken highly of及makes a contribution to 等这些词组的运用也让文章增色不少。