问题1：推荐信的最佳字数是多少?好像说是300-400，但怎么好多人写的篇幅跟PS似的，何况我的三个推荐人，除一个比较熟悉我可以写出detail之外，另两位仅仅是教过我课而已，这样要怎么写内容，字数多少合适呢?
回答：一般来说，推荐信字数a4纸用5号字写占3/4张纸即可，没有具体要求。
问题2：因为我没有网申过，所以不大明白。推荐信有一定格式吗，比如称呼，落款，日期什么的。
回答：推荐信的格式有些模式可循,以下将针对各段提供模式作参考：
(一)抬头可用的格式有：
Dear Sir/Madam;
To Whom It May Concern:
(二)第一段：引文句子可以引用如：
“It is a pleasure to recommend to you (name), a former student of mine at (name of university).”
“I an very happy to have this opportunity to recommend (name), who is presently applying for admission to your graduate (or undergraduate) program in (name of program).”
“I understand that (name) is applying for admissions to your graduate (undergraduate) school, and has requested that I write this letter of recommendation for her/him.”
“In my capacity as professor at xxxx University, I have known xxx for three years, as both his/her advisor and professor.”
(三)第二段：这段可以提供最实质的内容。譬如,如果推荐者是教授, 解释学生在他门下所修的课程。
“(name) took two of my courses during the 1984-85 academic year, as follows; “xxxxx” and “xxxxx”.”
“(Name) was enrolled in three of classes from September 1984 to June 1986 “xxx” and “xxx”.”
接下来,教授写一些有关申请人在课堂上的表现,如完成的研究计划、实验室研究、研究报告、考试的成绩、课堂态度、讨论课的参与等,举出实例。
“In my class (es), (name) did excellent work. She always listened attentively, participated activitely in class, and handed in very good written assignment.
“In particular, his/her research paper on (topic) was of exceptionally high quality, and showed that s/he fully understands and has a strong background in his/her field.”
如果推荐人是工作主管,首先一定要仔细陈述申请人的工作职责,并对申请者工作表现作一评估。如果可能的话尽量列举实例。
“When (name) held the position of (job title) in this company she was one s/he was one of my best employees. His/her job responsibilities included (describe them), and s/he carried out his/her duties with exceptional skill and professionalism.”
“S/he not only did his/her own work, but also helped other employees, and made many valuable contributions to the efficient running to our firm.”