Write a letter according to the following situation: the Wenchuan earthquake has made this winter extremely difficult for the victims. Write to tell your friend Smith that you are raising money to buy 200 pieces of cotton-padded clothing and some other necessities for the earthquake victims. Ask him to join the charity and show your appreciations for his help. Don’t forget to tell him your phone number 555-5555 for further discussion. Please sign your name as Li Ping. （150-200 words）