【正确答案】 Dear Mark,
I am sorry that I have forgotten to return you the book Gone With the Wind when I left New York. I was in such a hurry that I packed everything in my luggage without checking carefully.
I know you like this book very much, and it is a collective edition. My friend Jane is going to New York next month. If you don't mind, I can ask her to bring you the book then. But if you want it back urgently, I can send it to you by express mail.
Please let me know which solution you prefer. Sorry again for my carelessness.
Sincerely yours,
Li Ming

【答案解析】 这是一封正式的致歉信，语言要诚恳，由于涉及的是一本书，不是太贵重的东西，因此切忌语言夸张。提出的解决方案要合情合理。第一段表达歉意，并说明原因。第二段提出两种解决方案。第三段询问对方意见，并再次道歉。