Dear Tina, Thanks for your inviting me to your birthday party. At first, please allow me to give my best wish to you. Happy birthday to you. If I had time I would attend your party, but I am really busy. Because my father works in Shanghai and my mother is ill in bed, so I have to take good care of my mother. In addition English exam is coming, and I'm preparing for it. So I'm really sorry that I can't go for your party. Please forgive me. Thank you! I hope you can have a great and successful party.
