求一篇英語作文,假設你是劉瑩,星期天是瑪麗的生日,可你有是不能赴約,謝絕她的邀請,要說理由

題目：

求一篇英語作文,假設你是劉瑩,星期天是瑪麗的生日,可你有是不能赴約,謝絕她的邀請,要說理由
開頭是這樣的
Dear mary
Thank you for invitng me to your birthday party.I am sorry that 要接下去

解答：

(我是初二的)I can't visit you join your party.I have some really important things to do.My aunt was ill in the hospital but my uncle has a important meeting and he should go to Shanghai for four days.During his absence from Shanghai,I have to look after my aunt because I'v promised my uncle.Ill send you my gift and birthday card by mail.Yours LiuYing