One possible version:
Dear Tim,
I’ve received your email, asking me about my plan for the summer vacation. Now let me tell you something exciting.
I’ve applied to be a volunteer for the World Expo 2010 Shanghai and I’ll start working as soon as I have finished the entrance examination.
The exposition is a grand intermational gathering, which is expected to attract 70 million visitors from both home and abroad. And what makes it unique is that it is being held in a developing country for the first time. Can you imagine how proud I feed to be able to do my bit for this special occasion?
Speaking of the volunteer work, I’ll mainly help out in Beijing Pavilion, where I will show the visitors around and introduce the magnificent buildings to them, such as the Forbidden City, the Bird’s Nest and so on. It’ll be a good chance to help the visitors to get to know about the culture of Beijing. Apart form my work as a volunteer, I will certainly pay a visit to different pavilions., I won’t miss seeing the great inventions and achievements on display and I can experience different cultures as well as exchange ideas with people around the world. Sounds fantastic, doesn’t it?
I hope you can come and see it for yourself.
Fondly Yours,
Li Hua
略