Today, I write this letter of guarantee to you with guilt, to show you my bad behavior of playing mobile phone in class and my determination to correct my mistakes!

I will pay attention to the diligence of taking notes in class and delving into problems after class. No tricks in class, no cell phones. I don't know much about this kind of thing at ordinary times, which leads to this kind of thing. While writing this guarantee, I really realized my mistake. Thirdly, my behavior has caused a very bad influence on my classmates at school and damaged the image of the school. Students should learn from each other and promote each other, but my performance has brought a bad head to the students, which is not conducive to the construction of the style of study in schools and departments. The teacher cares about us very much and loves us very much, so I will listen to the teacher in the future and fully understand the teacher's requirements for us to ensure that similar things will not happen again. I hope the teacher can give me a chance to turn over a new leaf. Teachers want us to become pillars of society, and I deeply feel the hatred of teachers through this incident.

I sincerely accept criticism, and I promise I won't play tricks in class in the future. I can't play with my mobile phone, and I can't take classes seriously! I implore the teacher to believe that I can learn from my mistakes and correct them.

Your student XXX

Date, year and month