Dear Sarah,
I am terribly sorry to tell you that I am unable to attend your birthday party next Thursday evening. That is owing to(因为) the fact that (同位语从句)my younger brother suddenly fell ill and was taken to a hospital this morning. I have to go there immediately and take care of him. As told by the doctor in charge, it will take around five days for him to recover and I have asked my boss for a leave.
I really regret that I cannot go to celebrate your birthday personally and would miss the perfect chance of enjoying myself with all our old friends. I have chosen a small gift for you and will send it to you tomorrow to show my best wishes. Besides, please give my regards to our friends when you meet them at the party.
Cordially, (sincerely)
Li Hua
Dear Charlie,
Kindly excuse me for my not being able to see you off at the airport this Saturday as I have promised.
A major business partner of our company will be attending an important conference in Xiamen this weekend, and my boss finally chooses me to accompany him there to negotiate about a new transaction. I have just been informed of this plan and am happy about the decisionthis is an opportunity to both display and enhance my abilities, so I am afraid I cannot be present at the airport.
Pursuing study overseas is an essential step in the accomplishment of your dream.
How I wish I could have the chance to share with you my personal feelings and suggestions before you are away! I hereby send you a gift to wish you good luck. Please forgive me.
Cordially,
Li Ming