Dear Mr/Ms XXX：
Today I'm writing to you to ask for a five-day leave, for I've got cold last night with carelessness.
This morning my mother took me to see the doctor, who told me to stay in bed for some days. So I am very sorry to be absent from school, especially your interesting lessons. I'll be sure to make up for the missed lessons after I recover from the illness.
I got a bad cold beacause there was a heavy wind while I wore a little yesterday .Today morning I felt terrible and my mother found that I had got a fever,so she took me to see a docor and the doctor advised me to stay in bed and have a good rest.I have to ask you for two days of sick leave.I hope you can permit it .Thank you very much.
因昨天刮大风，自己穿的衣服又少患了感冒。今天早上觉得不舒服，你母亲发现你发烧(get a fever），便带你去看了医生。医生说你需要卧床休息2天，特向黄老师请假。
one possible version: 一个可能的版本: june 8, 2005 2005年6月8日 dear sir, 亲爱的先生, i'm sorry to tell you that i can't go to school today, i've caught a cold because i swam in the school's swimming pool yesterday. 我很遗憾地告诉你,我今天不能去上学了,我感冒了,因为我昨天在学校游泳池游泳。 this morning i had a headache. after taking my temperature, my mother found that i had a high fever, immediately she took me to see a doctor, who advised me to stay in bed for 2 days. now i am writing to you to ask for 2 days' sick leave. 今天早上我有一个头痛。之后我的温度,我妈妈发现我发高烧,她立刻带我去看医生,他建议我卧床休息两天。现在我写信给你要求2天的病假。 with best wishes 并致以良好的祝福 your students, 你的学生, tom 汤姆
I‘m sorry that I have to ask for a leave because I have been ill.I want to go home and return two days later.I hope that you can do me the favour.