Dear Mr.Smith,
How are you?
Thank you so much for inviting me to the English corner!However,I would like to extend my sincere apology to you,because coincidently tomorrow is also my brother's wedding,I have no choice but to quit participating the English corner.Actually I really like the english corner,so I am wondering if it is possible that I could join it on next period?
Look forward to your reply.Your understanding will be highly appreciated.
Sincerely,
Li Hua