答：请假条(written request for leave)是英语学习者必须掌握的常用应用文之一，它包括请病假(note for sick leave)和请事假(leave of absence)。请假条是用于向老师或上级领导等因身体状况不好或因某事请求准假的场合。
Hello. Mr Brown,I am sorry that I can't take the listening class on December20th. Because I have something urrgent to deal with. My uncle has to deal with something about his business but he can't find a proper interpreter so he hopes that I can be his interpreter on that day. I would like you to give me a day off .I would appreciate it if you can consider my condition.
Dear Mr Chen,
I'm sorry to tell you that I can't go to school today. I've caught a cold because I swam in the Kunming Lake 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 two days.
Now I'm writing to you to ask for two days' sick leave.
Dear Miss Ding:I’m sorry to tell you that I’m not feeling well today. i have a feber and the doctor told me to stay in bed for two days.so i can't go to school today.if i get well very soon,i hope i can go to school tomorrow.thank you