最后在推荐信用的纸张、信封、字体、字号、段落等方面尽量避免雷同。
4、绝对避免语法、拼写或明显的用词错误。
下面是一篇较好的推荐信，请大家体会一下这些原则的运用。
In capacity as Professor of Mathematics at Fudan UniversityI＇m writing to recommend Mr. WangGesintosyour PhD program in Computer Science. I have known Mr. Wang since his sophomore year of collegeand have acted as his thesis advisor and mentor. In my experiencehe is a gifted and diligent studentand an admirably hard worker. 
Wang is an impressive student because he has been forced to overcome the significant challenge of a serious illness during his freshman year. When I first met Wang in my Discrete Math classhe did not appear to be anything special to me. While his exam scores were goodthey were not as high as I would now expect of him. What I didn＇t know then was that due to his illnessWang was attempting to take all of the difficult early mathematics courses at one timeincluding Discrete MathematicsAdvanced MathematicsLinear Algebraand Possibilities. While most students found preparing for just one set of these exams difficultWang was overwhelmed by four of them. But in the endhe achieved an impressive score on the final examwhich made me conscious of his unusual determination he demonstrates when confronting difficult challenges.
Mr. Wang and I have often talked about a variety of mathematics and computer science concepts and problems. During these discussionsI always found him to be delightfully intelligent. Not only does he quickly understand the concepts and problems presented to himhe is able to analyze these problems and present solutions. But perhaps most important is that Wang＇s thinking is intensely rigorous. When looking at any questionhe carefully scrutinizes it and if he finds any uncertain issueshe clears them up immediately. I believe this kind of thought is essential to become an excellent computer programmer. 
Serving as his thesis advisorI had a first-hand opportunity to observe the way in which Wang＇s mind works. In his senor thesisMr. Wang mainly discussed two challenging questions in regards to″ANN″. In our books in Chinaknowledge of ANN and its uses are very rare. Few people in China have studied this topic and consequentlythe materials that are available on ANN are limited. Working on this difficult projectnot only did Mr. Wang rise to the challengebut he went above and beyond the call of duty to analyze his secondary sources and test them for accuracy in practice. In this wayhe found mistakes in the book that we use. His diligence and hard work made me extremely proud of him. 
Mr. Wang is an intelligentmotivatedand industrious individual. Teaching and advising him has been a delightful pleasure. I know that if given the chance to study abroad in Americahe will arm himself to become a great programmer he dreams of being. He has the intelligence and background to achieve these goals - now