How to write an apology letter to the teacher?

Writing ideas and main points: Take the most serious fighting incident as an example, sincerely reflect on your mistakes and ensure that you won't make the same mistakes again in the future.

Text:

Dear teacher, I am writing this critical letter to you today with a feeling of guilt, to show you my understanding of the mistake in this battle and to promise not to make similar mistakes again.

I am ashamed of the mistake I made this time. I really shouldn't fight with my classmates. After calm thinking, fighting can't solve the problem, but it will make things worse.

I feel very sorry. I hope teachers and classmates can forgive my mistakes and give me a chance to show. I hope everyone can supervise my words and deeds in my future study and life. I will never let you down.