急求英语作文!关于李华的英语作文,100词左右

Dear Paul,
I have got your letter,and thank you very much for inviting me to your school's cultural exchange and the introduction of Chinese Traditional Paintings next week's.I am sure it would be a wonderful experience for me,there must be plenty to learn which I shall find it really interesting and a lot of fun.Unfortunately,I have a bad new to tell you.My grandfather has seriously taken ill.He is very old and I don't think I can leave him.Therefore I am very sorry that I have to turn you down,and won't be able to attend.But I have a class friend Anna who is very interested in such studies and she would like to go in my place.Would you welcome her?Please let me know as soon as possible.
Best friend of yours
LiHua