Dear Ms. Evans,
I have been your student for three long years, and the things that I have learned from you will forever guide me, as I go through life on my own.
As you very well know, I will be graduating this year. It will be a very important occasion in my life and I want you to be a part of it. This letter serves as my invitation to you. I wish that you will not turn me down. I have only invited those people who were so important to me and you are one of them. Your presence will greatly honor the occasion, as you have done to me during the three years that I have stayed with the school.
There will be a small party at the house after the graduation ceremonies. I wish you will be there too. My parents are expecting you and they are looking forward to meeting you.