解释信模板英文

Dear Dina, I am indeed sorry that I can not attend your birthday party,beacause I must prepare my exam on weekend.For me ,it is very important to attend the exam on Monday.Hence,I feel badly about it and want you to knoe what happened. Here,once again,I am sorry for it. Sincerely yours, Alice

Dear sir, Refer to your request for the certificate of my parents deposit account in the bank to facilitate my Visa application. As you may know, I would have no difficulty to obtain the said necessary document from the bank. however, both of my parent's income were lodged in one bank account under my father's name. Therefore we hope that the deposit certificate which issued only bears my father's name would be sufficient for your needs. Thanks for your understanding in relation to this and we would obliged to furnish further documents as you may require. Kind Regards (your name)

First of all thank your school in the process of applying for a visa for their help, but now I can only regret the decision to give up the chance to study in exchange. The visa application failed to pass due to incomplete data so the embassy audit, now school has started, re-apply if they have to spend at least a month's time, is bound to delay a lot of courses. So now I can only regret the decision to give up this opportunity. Inconvenience this may cause, and I am very sorry. Hereby offer an explanation to this letter to express my apologies.首先非常感谢贵校在申请签证过程中给予的帮助，但现在我只能遗憾的决定放弃这次交换留学的机会。 这次签证申请因资料不全所以未能通过大使馆审核，现在贵校已开学，若重新申请至少还要花一个多月的时间，势必耽误不少课程。所以现在我只能遗憾的决定放弃这次机会。由此造成的不便，我感到万分的抱歉。特此奉上这封解释说明信以表达我的歉意。

留学新西兰所需的英文解释信应怎么写？是怎样的格式？Studies in English which New Zealand needs to explain how the letter should write? Is what kind of form?