Dear Mr. Wang，
I am very sorry that I shall be unable to e to your classes today owing to a bad cold. I enclose a certificate from the doctor who is attending me. He said it will be two or three days before I shall be able to resume my school.
Yours，
David
敬爱的马老师：
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。
您的学生
李丽
Dear Miss Gao,
I'm sorry I can’t go to school today. I helped the farmers pick apples with my classmates on the farm yesterday. Unluckily, I fell off the ladder and hurt my leg, but I want badly hurt. The doctor asked me to stay in bed and have a good rest. So I ask for leave for two days.
Your student
Wang Li
Dear Sir or Madam,
I beg to apply for two days’ leave/a week’s leave/7 days’ leave of absence from the 7th to 8th of this week. Because I was ill, I want to return/go home to see the doctor.
To support my application, I herewith/enclose the sick leave certificate.
I should be very much obliged if you will grant me my application. As regards the lesson to be missed during my absence, I will do my best to make them up as soon as I get back from leave.
Yours respectfully,
Li Min
Dear Ms.Riddle，
I would like to know if I could ask for a casual leave of absence from your Oral English class this Wednesday morning.
Yesterday evening I got a phone call from my cousin, who is now running a small firm in suburbs of this city . He needs an interpreter for two days but cannot find the most reliable person，so he wants me to have a try. Personally，I regard this as a golden opportunity to put what I have learned in your class into practice，but I need your permission of absence . If you think I may go and help him get over the difficulty，I am confident that I ll do a good job and both of us will grateful.
Earnestly yours，
Sam
Dear Prof. Wang，
I am very sorry to apprise you that I am unable to attend school today owing to a bad cold. I enclose doctor’s certificate and ask you for sick leave of three days.
Your student
Tom
敬爱的马老师：
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。
您的学生 李丽
Dear teacher:
I'mxx.I'm sorry that I can't go to school today.Because I have a fever.I feel very bad now.So I want to stay at home to take a rest.I hope you can permit me to stay at home.
Yours.
xx