写作思路：把自己请假的理由写下来。
Dear XXX
亲爱的某某某
I'm writing to notify you that I won't be able to make it to work/school today due to illness. I am awefully sorry for the short notice and any inconveniences that my absence may bring to you. According to the doctor, I should make a full recovery within 2 days. So， I should be back to work/school the day after tomorrow.
今天去函想告知你，我今天因病无法去上班/上学了。非常抱歉这么晚才通知你。由于我的缺勤或许会给你的工作带来诸多不便，对此，我深表歉意。医生说了，我的病两天就会好的。所以，我后天就会去上班/学。
Thank you for your patience and understanding.
谢谢你的耐心和理解
Best regards
谢谢你的耐心和理解
YYY
诚挚的某某某
写作思路：把自己生的病情况写清楚，表达出自己不得不请假的缘由，最后表示出自己会努力追上学习的决心。
正文：
Dear teacher x：
尊敬的x老师：
I am writing to you today for a five-day holiday because I had a cold yesterday night.
我今天给您写信是要请5天的假，因为我昨天晚上不小心感冒了。
This morning, my mother took me to see the doctor. The doctor told me to lie at home for a few days.
今天早上，我妈妈带我去看了大夫，大夫告诉我要在家里躺几天。
Therefore, I feel sorry for my absence from class, especially not being able to attend your interesting class.
所以，我对缺课，特别是不能上您那有趣的课，感到难过。
I will make up for the missed lessons when I get well，I beg your pardon。
我病好后一定把漏掉的课程补上，希望您原谅。
Sincerely
此致
Salute your students: XXX
敬礼您的学生: xxx
I'm writing to notify you that I won't be able to make it to work/school today due to illness. I am awefully sorry for the short notice and any inconveniences that my absence may bring to you. According to the doctor, I should make a full recovery within 2 days. So， I should be back to work/school the day after tomorrow.
Thank you for your patience and understanding.
Best regards,
YYY
亲爱的某某某，
今天去函想告知你，我今天因病无法去上班/上学了。非常抱歉这么晚才通知你。由于我的缺勤或许会给你的工作带来诸多不便，对此，我深表歉意。医生说了，我的病两天就会好的。所以，我后天就会去上班/学。
谢谢你的耐心和理解
诚挚的某某某本回答被提问者和网友采纳
请假条应该言简意赅，作为批假的人也会提高批假的效率，不做无谓的情境描述。
英文版：
Dear teacher / leader,
I'm Lily. I 'm not being myself today. I feel awful. My throat is very sore and I got a cold fever. Would you please give me several days off ? I want to ask 3 days for sick leave. I really hope to get your approval. Thanks for your time.
中文版：
尊敬的老师/ 领导，
您好，我是李丽。 我今天身体不舒服，感觉特别难受。我喉咙发炎了，也有些感冒发烧。您能给我请假看病吗？我想请三天的病假。望批准为盼。谢谢您！