(Name and address of school)
SUBJECT: TELLING THE REASON OF ABSENCE
Firstly, I would like to inform you that I am a student of class(your class along with section). I was absent from the last 2 days because of I was delayed in getting up in the morning. This was done due to a personal problem. Actually, I am staying alone at my house from the last 2 days. So, there is no one at my house to wake me up and I do not have any alarm clock too. That is the only reason why I missed my class. I hope that you will understand my problem.