1. Please excuse my late reply to your very friendly letter of March 1.

　　2. I hope you will forgive me for not having written you for so long.

　　3. I hope you will excuse me for not having replied to you until today.

　　4. I humbly apologize you for my delay in answering to your kind letter of May 5.

　　5. I have to (must) apologize you for not answering your letter in time.

　　6. I must ask you to kindly accept our excuses, late as they are.

　　我们对您的关照，谨致谢意，等。

　　1. We request you to accept our warmest thanks for the anticipated favour.

　　2. We thank you in advance for the anticipated favour.

　　我们时刻不忘尽我们所能，为您服务，等。

　　1. We assure you of our best services at all times.

　　2. We shall spare no efforts in endeavouring to be of services to you.

　　3. We shall be pleased to be of service to you at all times.

　　请原谅给您添了麻烦，等。

　　1. We hope you will pardon us for troubling you.

　　2. We regret the trouble we are causing you.

　　3. I regret the trouble it caused you.

　　4. We trust you will excuse us for this inconvenience.

　　5. We wish to crave your kind forbearance for this trouble.

　　6. We solicit your forbearance for such an annoyance.

　　7. We trust you will overlook this botheration, which we exceedingly regret.

　　8. Kindly excuse me for troubling you in this matter.

　　请宽恕某某事项，等。

　　1. Please excuse this clerical error.

　　2. We tender you our apology for the inconvenience this error may have caused you.

　　3. We request you to accept our regret for the error of our clerk.

　　4. We greatly regret that we have caused you such a inconvenience.

　　5. We wish to express our regret for the annoyance this mistake has caused you.

　　6. We frankly admit we were at fault and we are anxious to repair the consequences.

　　请多加关照，等。

　　1. We solicit a continuance of your valued favour.

　　2. We solicit a continuance of your confidence and support.

　　3. We hope we may receive your further favour.

　　4. We hope to receive a continuance of your kind patronage.

　　5. We request you to favour us with a continuance of your kind support.

　　6. We solicit a continuance of your kind patronage.

　　　如有机会，我们必会报答您，等。

　　1. It would give us a great pleasure to render you a similar service should an opportunity occur.

　　2. We wish to reciprocate the goodwill.

　　3. We shall on a similar occasion be pleased to reciprocate.

　　4. We hope to be able to reciprocate your good offices on a similar occasion.

　　5. We are always ready to render you such or similar services.

　　6. We shall at all times be willing to reciprocate such or similar favour.

　　7. We shall be happy to have an opportunity of reciprocating to you on a similar occasion.

　　今天我已经讲完应报告事项，等。

　　1. With nothing further to add today.

　　2. With nothing more for today.

　　3. Without anything further for the present.

　　4. With nothing further for the present.

　　5. Without anything more to communicate for today.

　　6. Without more to write you by this mail.

　　7. Without further to advise you today.

　　8. We have no more (nothing further) to tell (inform) you today.

　　这些总结的雅思G类写作的商业书信结尾都是以最简单的结构为例子的，大家在考试的时候一定要根据自己的实际情况，适当的添加各种句子成分，使之更加饱满，更加丰富。