One possible version:

Dear principal,

I am Li Hua, monitor of class 1, senior Grade 3. I am writing to report us students’ opinions on our PE classes being cancelled.

Facing the coming college entrance examination, we Grade 3 students all feel stressful. One of the effective means of reducing our pressure is taking exercise including having PE classes. That is why my classmates felt frustrated and helpless when hearing your decision. We believe taking exercise can keep us more healthy, more energetic to improve our grade. It can also strengthen our friendship and we can do less for more when learning. As the saying goes: All work and no play makes Jack dull boy. Considering all the above, we sincerely hope that you do not cancel our PE classes therefore. By the way, having one more PE class each week is welcome. Thank you!

Yours

Li Hua

题目分析：本文是一篇材料作文，比较简单，学生很容易把握写作的要求和目的。学生在写作之前必修认真审题。这是写给校长的一封信，首先要介绍自己，然后说出自己的目的，并且说明理由，最后写上自己的希望。一般给领导写信都是这样的。

【亮点说明】文中使用了一些信件中的常用语，如：. I am writing to ……这是说出写信目的的常用语。另外还用了一些分词做状语的结构，如：Facing the coming college entrance examination, we Grade 3 students all feel stressful.从句，如：That is why my classmates felt frustrated and helpless when hearing your decision.这些为文章增色不少。