【参考思路】一、表明写信目的：申请参加该活动（添加得知消息）
二、选择一种分享方式：二者选一
三、阐述理由
四、书信结尾（添加希望）
【参考表达】
一、写信目的
1. I’m writing to tell you that…
2. The reason why I write (this letter) to you is that…
3. I am writing to you for the simple reason that…
4. My purpose of writing this letter to you is that…
二、表示选择的表达句式
1. Between them, I would like to choose…
2. Of the two, I prefer the latter to the former.
3. By comparison, I would pick the latter rather than the former.
4. Of the two, the latter is my preference.
5. Of the two, the latter wins my favor.
三、原因句式（见作文一）
四、表示希望的表达句式
1. I am looking forward to more information.
2. I would appreciate it if you would offer more information.
3. Your detailed message will be much appreciated.
4. If you could provide more specific information, I would be much grateful.