Dear Lily,
I am so sorry to tell you that I lost your English store book, which I borrowed last week.
I have read it. But after finishing it, I left it in the library. I returned to the library as soon as I relized. Unfortunately, I didn't find it anywhere I stayed in the library. I will buy a new one as an amends. I hope you accpet it.
Sorry again for the book.
Yours, Mike