how to write the letter to anyone for expressing his or her things by mistaken

Dear Student,
Your query cannot be understood. Given below is an outline to your question. Work on this outline to frame a complete answer, as this is a creative writing task. Refer to the Website to find the format of a letter.

• I am writing this letter to express my apology for having taken your book by mistake.
• I suppose your book got into my custody while we were having our combined study class.
• I am sorry that I did not remember to return it.
• I hope you will forgive me for the same.

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