a letter of refusing an invitation

　　the number 25 middle school, beijing june 10th nanjing university, nanjing.

　　dear mr smith,

　　i am very thankful to you for inviting me to go and stay with you in nanjing. i often hear that nanjing is a beautiful city and i have been a long to see you again so that i can get more help from you in my english study. but i'm afraid i can't go this coming summer vacation.my grandmother who lives in the country has asked me again and again to go and spend the vacation together with her. she misses me so much that i have no choice but to obey her. i am busy preparing for my college entrance examinations all these days and now i felt quite sure of myself. just wait for the second news of my success. i wish i could go and see you and tom at the end of this year. with best wishes to both you and tom.

　　yours sincerely

　　lihua.