dear mr. li,

　　i'm sorry to tell you that i'm not feeling well today. i've had a headache and a cough. i didn't sleep well last night. i went to see the doctor this morning. the doctor told me i had caught a cold, and i should stay in bed for two days. so i'm afraid i can't go to school today and tomorrow. i hope i'll be all right and go back to school the day after tomorrow. thank you.