It's a pity that I have to tell you a bad news.
Something incredible happened to me last weekend. I had a car accident and my legs were broken. Therefore, I have to notisfy you that I cannot go to university in the next few weeks due to this serious accident. So I need to ask for half a month's leave. Thank you for your understanding and I'm waiting for your approval.
Enclosed herewith is my medical records and proof issued by the hospital leave
I am sorry to hear that you hurt in an accident. To be careful while you are in bed. Don't think of doing any homework. You can watch television or listen to radio programs to help pass the time while you recuperate.
We all miss you very much and shall be happy when you return.
Wish you be back as soon as possible!
I have seen your application for sick leaving. I am sorry to know you are hurt. You don't need to worry your study. If you have something unclear, you can ask me for help when you go back to the university. How is your condition? We all worry about you. We will go to see you in this weekend.
Wish you a speedy recover!