Monday,5th July
Dear Professor Martin,
I apologize for being absent in your class yesterday. But I did not mean it. My friend fell from the bike and broke his leg by accident, so I had to take hime to the hospital. I do enjoy your class and I feel so sorry to be absent. Please give me an opportunity to make up the missed lesson. I know you prefer us to ask for leave in advance, but it was very urgent and unexpected at that time. I hope you can accept my apology. Thank you.