【正确答案】[范文]
Dear John,
   I am sorry to tell you that I will not be able to attend your marriage ceremony. Now I am writing you this letter to apologize for my absence.
   As your good friend, I really hope to witness your special moment. But unluckily, I will have to attend an important job interview whose scheduled date happens to fall on the day of your wedding. The interview matters a lot to me, and as you know, I am longing to secure a job in a multinational company and have been preparing for this for quite a long time. I do hope you can understand and forgive me. And it would be considerate of you to give me another chance to have a party with you afterward. If so, please drop me a call about your preferable date. I am looking forward to your reply.
   Once again, many apologies for the absence from your special day, and please take my sincerely blessing to your wedding and wish all of you a good time. Happy marriage!