A Letter To A Classmate
Dear Mike,
I am writing to say that I'm sorry for forgetting to give back/return your English grammar book. I've been too busy these last two weeks, because I am preparing for a (an upcoming) sport event.
I know that some material from the book will be studied for your next semester/ I know that the material in this book will be covered next semerter OR I know that you will be studying the material in this book this upcoming semester, and so I suppose it can be important/essential for your studying. If so, really I really need to find a way to send this book to you.
I'd really like to solve this mistake/situation as quickly as possible. I might scan copies of every page if you need to get it soon, but If you have some time to wait, I can send you the book using a postal service/by mail. Please, drop me a line to let me know about your decision/preference.
Your friend and classmate,
Sergei