求翻译：随着全球经济一体化进程的不断发展，世界范围内的经济合作与交流也不断增多。人们不可能跟自己的贸易伙伴一一亲自会面协商。而且我们常常需要将自己的贸易伙伴做出的各种承诺变成有籍可查的文字记录。这时商务信函就成了取代亲自拜会的一种便宜有效的沟通媒介。我们给贸易伙伴的每一封信都代表着自己所在公司的形象，显示着公司的水平和实力。优秀的商务信函在我们发展同客户的关系，以及达成新的业务方面起着积极的作用。所以在写作时我们应该严格遵守并且灵活运用“7C”原则： Completeness（完整）Concreteness（具体）Correctness（正确）Conciseness（简洁）Clearness（明晰）Courtesy（礼貌）Conscientiousness（诚意）。这七个原则是商务英语信函写作最基本的指导原则，对于写好一封商务信函起着很重要的作用。在商务英语信函中使用礼貌用语,是开展及进行现代商业活动的重要前提。本文对礼貌原则进行了详细的剖析，使用大量的例子对其进行分析与对比，对礼貌原则的运用进行了解说,旨在帮助读者提高在商务英语信函中使用得体的礼貌，以促进商务往来。是什么意思？

With the development of global economic integration, economic cooperation and exchanges in the world have continued to increase. One cannot one by one with their trading partners meet in person consultations. And we often require their trading partners made various commitments into subjects available written records. Replaced then became a business letter to personally call on a cheap and effective communication medium. Our trade partners to each letter represent their organization's image, displayed at company level and strength. Excellent business letters in our developing relationships with customers, and play a positive role in new business. So at the time of writing, we should strictly observe and flexibility in the use of "7C" principles: Completeness (full) Concreteness (concrete) Correctness (correct) Conciseness (concise) Clearness (clarity) Courtesy (polite) Conscientiousness (good faith). The seven principles are the basic guiding principles of business letter writing, writing a business letter plays a very important role. Use of politeness in business letters, and modern business activities is an important prerequisite. To a detailed analysis of the politeness principle in this article, using a large number of examples on the analysis and comparison, to understand the application of politeness principle says, is intended to help readers improve business letter used in proper manners, to promote commercial links.