One possible version:
Dear Miss Morgan,
I’m so sorry that I won’t be able to attend the lecture on American culture tomorrow afternoon.
My uncle is returning home from France , and I’ve promised to meet him at the airport at 3:30tomorrow afternoon.
I’m very interested in American society and culture. I wonder if it is possible for the talk to be recorded , and if so , could I borrow the tape? It would mean a great deal to me to listen to the tape and make up for what is covered in the talk. I would appreciate it if you could allow me to ask for leave of absence.
Thank you .
Yours sincerely
Li Hua