【正确答案】[参考范文]
Dear Mr Li，
I have got a bad cold and a headache this morning,probably because of the changeable weather．I went to see the doctor early this morning，and he advised me to stay at home and have a rest for several days．So I can't go to school these days．1 will study at home and will try my best to catch up with the lessons after I'm well and come back to school．Thank you．