This is very common and most important requirement of the school students. Many know the technique of writing the letter , but feel fear and problem while writing the reason in the application. I want to clarify this thing. Think, if your need is justified then you have to write excuse without any fear. This is the straightforward rule of writing leave application. also don't be shy of writing one reason or excuse many time.
So here is the sample application.
Date March 25 , 2013
XXX School, XXX
Sub: Leave application.
Respectfully I want to say that I was suffering from fever/cold/ headache / stomach pain for last two days from 23-03-2013 to 24-03-2013. During this period I could not attend the school.
I, therefore . request you kindly grant me a leave of two days and oblige.