Dear Johe: I am Lihua, I'm so happy that receive your invitation for dinner in your house. But i have to tell you a bad news,It's so unfortunate. In that day, I have a exam.I have to go to school invent the exam. It's important for me. So i can't have dinner with you. What a pity , we have a long time to meet each other. I am so sorry miss this change. In here. I hope you have a wonderful dinner. I will come to see you before I finish the exam. Please feel free to look forward to it。 Your Friend Li Hua