Dear Mr. and Mrs. William，
I've learned that you are interested in Beijing Opera, so I've come to give you two ticket for tomorrow evening's Beijing Opera at Mei Lanfang Theater. But it's real a pity that you happened to be out. So I have to leave the tickets with this note. The opera will be put on by some famous actors or actresses. He is well worth watching. By the way, I've read the two books you lent me, that are very interested. This week, I am busy review my lessons in order to pass the final exams. I'm afraid of that I can't go to the Opera together with you.
I hope you will have good time.