Dear Mr Liu,
I'm sorry to tell you that I can't go to school today. I've caught a bad cold because I was caught in the rain yesterday.
This morning I had a headache. After taking my temperature, my mother found that I had a high fever. She took me to see a doctor. The doctor advised me to stay in bed for three days.
Now I'm writing to you to ask for three days' sick leave.
Li Na
【参考译文】
亲爱的刘老师：
很抱歉我今天不能上学了。我患了重感冒，因为我昨天让雨淋了。
今天早上我头疼，妈妈给我量体温后发现我发高烧。她带我去了看了医生。医生建议我卧床休息三天。
我现在向您请三天病假。
李娜