急求一篇英语作文假如你是十三中的李华,你和汤姆约好下周末去北京旅游,但你因故不能赴约!要求：写一封电子邮件 1要表示歉意

Dear Tom,
I am so sorry to tell you that I won`t be able to come with you for the trip to Beijing.Because I will have to take part in a speaking contest next weekend.We have an appointment with another time.
Once again,I am so sorry and I wish you a pleasant time in Beijing.
Yours Sincerely
Li Hua