楼上写的蛮好,是标准格式,考试上可以这么写,但是日常没必要这么啰嗦.直接这么写就行.
January 5th 2010
Dear Sir,
I'm sorry to tell you that I can't go to school today,I've caught a cold last night,and I feel really bad this morning.
So I want to ask for one day's leave.
Sorry for being absent.
Best wishes
Your student
.