王红收到李强的邀请信,邀请周末去他家聚会,但王红母亲去上海经过她这里要小住,

Dear Qiang Li,
I am very sorry to inform you that I will not be able to come visit you this weekend.My mother and I went to Shanghai and we intend to stay there for a few days.My mother wishes to buy a nice dress for my sister who is living in Shanghai at the moment.Thank you for the invitation,I will surely come next time!I wish the best for your family.
sincerely,
Hong Wang