Dear Mary,
I am very sorry that I was out when you came to see me yesterday afternoon. The fact is that I had an engagement with some friends and, ignorant of your visit, accompanied them to the cinema. Not until nine oclock in the evening did I come back. You must have been disappointed by my absence.
I hope you will not leave the city this week. I will call on you on Friday afternoon at four oclock. As this is the first time you come to Beijing, I will take you to some places that may interest you. Please wait for me in your hotel at the appointed time.
Yours truly,
Xiao Cheng