Dear Mr. Zhang
I am so sorry I did not finish my book report. I was sick during the time period you gave us to do it.I want you to know that I will get it done as soon as possible. Please forgive me for this one time. As you know, I usually get my assignment done on time, this time is only an exception dur to my illness, I hope my mistake will not effect your works on marking the report. Again, I am really sorry.
Regards,
Lihua