Suppose you have made an appointment with Mr. Smith for a business talk this Friday afternoon. Now your manager has asked you to go to Beijing on business and you won’t be able to return until next Monday. Write a note of apology to Mr. Smith.假设你与史密斯先生原本约好了本周五下午开会,现在经理却要求你去北京出差,你要到下周一才能返回。请写一封英文的道歉信给史密斯先生吧。注意英文书信的格式。