【答案解析】Dear Bonnie,
Now I am writing to you to express my apology for the damage of your computer during my stay in your house when I visited Guangzhou a few days ago.
It is just because of my carelessness that I damaged your computer. I understand that it must have brought you a lot of trouble and inconvenience so I feel extremely guilty for what I have done to you. In order to compensate for your loss, I decide to buy you a new computer and send it to you by EMS.
Please accept my sincere apologies and forgive me for my ridiculous carelessness.