Jim邀请Lily参加他这周日的生日宴会，但是Uly 的父母出差要到下周才回来。爷 爷又卧病在床，需要人照顾，加上数学考试即将来临。因此，Lily无法前去参加生日宴会。Lily感到很抱歉，只好写信辞谢。根据中文提示写一封60-80词的信(出差on  business)  
Dear Jim,    
     Thank you very much for inviting me to your birthday party. I'd like to go but I can't. My  parents…
_________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________                                                                
                                                                                                                                                 Yours,
                                                                                                                                                    Lily