The first paragraph: tribute and opening remarks, expressing sincere respect and greetings to the teacher. Express directly that you want to write this letter to express your gratitude to them. The second paragraph: the specific reason and its influence, express deep gratitude to the teacher for finding your lost meal card. Explain how important this meal card is to you, and how much convenience and peace of mind it has brought you after being retrieved. The third paragraph: Thank you again and look forward to the future, express heartfelt thanks again, and mention its positive qualities such as selflessness and caring for students. He expressed his willingness to keep this kindness in mind and looked forward to better cherishing the opportunity to help others in the future. Conclusion: I would like to express my sincere and heartfelt thanks again and sign my name.