Dear Sir，
I take the liberty to write you in the hope that you might need someone to fill in for you. I feel that I am qualified as an administrator.
I am currently a student at college, I have over a month more to complete before I graduate. My major is business administration.
I have excellent grades in all my subjects. If you wish to look at these information it will be sent to you later.
I have worked at a trading company as a secretary, but I hope to seek more responsible employment.
I am 25 years old and very honest and dependable. If you need someone with my qualifications, please let me know.
thank you very much for your kind attention.
Sincerely yours