谁帮我写个.假设你是新华中学的学生李华你和在上海上学的英国朋友TOm约好下周末去北京旅游,但你因故不假设你是新华中学的学生李华你和在上海上学的英国朋友TOm约好下周末去北京旅游,但你因故不能赴约.请根据以下要点用英语给他写一封电子邮件:1表示歉意2解释原因(参加演讲比赛)3另约时间

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. can we fix another time?
Once again, I am so sorry and I wish you a pleasant time.
Yours Sincerely
Li Hua