Dear Ms Ma,

敬爱的马老师：
I apologize that I cannot go to school today. Last night my mother had a high fever and coughed badly. I think that she has got flu. She didn't have a good sleep and is very weak today, so I will go to Tiantan Hospital with my mother, and then stay at home to attend her. Because of this I have to ask for leave. I will appreciate you very much if you can allow my leave.

很抱歉我今天不能去上学了。昨天夜里我妈妈发高烧，咳嗽得厉害，我想她可能是得了流感。昨天晚上她休息得不好，而且今天很虚弱，所以我陪妈妈去天坛医院，然后在家照顾她。因此我不得不请假。如果您能准假我会非常感激。

Yours,
Li Li
您的学生 李丽

Dear Ms Ma,

敬爱的马老师：
I am sorry to tell you that I can't go to school today. Last night my mother had a high fever and a bad cough. Perhaps she has caught flu. I will take my mother to Tiantan Hospital and then look after her at home, so I couldn't go to school today. So I would like to ask for one day's leave. I will be very grateful if you grant my leave.

很抱歉我今天不能去上学了。昨天夜里我妈妈发高烧，咳嗽得厉害，她可能得了流感。因为今天我要带妈妈去天坛医院，然后在家照顾她，所以不能去上学了。因此我想跟您请一天假。如果您能准假我会非常感激。

Yours,
Li Li
您的学生
李丽