假如你们学校的学生肖明因严重心脏病需要手术，但他家庭困难，无力承担昂贵的手术费。校学生会(The Students’ Union)计划发起公益活动帮助他。请你根据以下要求，写一封呼吁全校师生伸出援手的公开信。
【要点】1. What happened to Xiao Ming?
2. What can you do help him?
3. ...
【注意】1. 词数 90 左右，开头和结尾已给出，不计入总词数。
2. 可适当发挥，使短文连贯、通顺。
3. 文中不得出现真实的人名、校名和地名。
Dear all,

The Students’ Union

Our schoolmate Xiao Ming is a kind and hard-working boy. Unluckily, he has got a serious heart problem now and he has to have an operation as soon as possible. But his family is so poor that they can't afford the high cost of the surgery.
To help him, the Students' Union will hold a charity sale on the playground this Friday afternoon. We also hope all teachers and students can donate some money to him. Even a small contribution means a lot to him. Let's give a helping hand together and help Xiao Ming get back to school soon.

本题为八年级要求掌握的公益呼吁类应用文写作，解题思路如下：1. 审题：明确文体是公开倡议书，时态以一般现在时、一般将来时为主，需覆盖所有要点，词数控制在90左右，使用本单元所学的公益救助相关词汇即可。2. 写作逻辑：首先清晰介绍肖明的遭遇，说明他急需手术但家庭无力承担高额费用的现状；接着说明学生会计划开展的帮扶活动，同时呼吁师生们自愿捐款、献出爱心；最后表达对大家的感谢，点明小的善意也能帮肖明渡过难关，重返校园。3. 注意语句连贯，避免出现真实校名地名，符合字数要求。