Dear Peter,

Thanks very much on inviting me to your birthday party on Sunday. I’d like very much come but I will had an examination on Monday morning. It is a very important exam but I can’t afford to fail it. I’ll spend all the whole weekend reading and prepare for it. So I’m really sorry that I won’t be able to come in this time. Hope you can understand. I’ll take this chance to wish you wonderful time on your birthday. Happy birthday, Peter, and many happy return of the day!

Yours,

                                Li Ming

Dear Rose，

Thank you very much on inviting me to your birthday party on Sunday．I’d like very much go but I’ll have a examination on Monday morning. It is very importance but I can’t afford to fail it．I’ll spend all the whole weekend reading and prepare for it．So I’m really sorry that I will be able to go this time．I hope you can understand me．I’ll take this chance to wish you wonderful time on your birthday．Happy birthday，Lily，and many return of the day!

Yours,

Mike