2. 必须交待与被推荐者的认识期间(何时开始认识或认识多久)，认识程度(偶尔见面 或密切接触)及关系(师生关系，上下级关系，同事等)。
3. 对被推荐者的优点介绍及评价，这是推荐信的核心。主要包括被推荐者的天赋，学习 成绩，研究能力，工作经验，学习精神，组织能力，品行及个性方面。
Dear Professor ******,
I am glad to receive your letter and the good news to Mr ******. As his supervisor, I have known him for more than five years, and I am pleased to give you a formal statement.
Mr. ****** graduated from ****** University and began his Ph.D. study under my supervision in ****** in ******. His research work mainly focused on ******. He was proficient in ******. Due to his hard work, a lot of progresses have been made in this years. I know that he have acquired a broad and strong experience in ******, especially in ****** study.
In my close contact with him, I was deeply impressed by his strong interest and enthusiasm in scientific research. Besides, he has fine ideas and can design reasonable plans for his research. From my observation, he can undergo a new research project independently and quickly because of his mastery of ****** techniques and quickly taking in new techniques.
Furthermore, he is also modest and easy to get along with, he showed high respecting to teachers or advisors. He energetically participated in some common affairs in the lab. These characters will allow him to adapt to a new environment rapidly.
Mr. ****** is one of the most studious and promising fellows among my students. I recommend him to you without any hesitation and expected that the postdoctoral experience in your laboratory will provide further refinement and specific training for him.
I have now received all three of your letters and they speak very highly of you. As a next step, I would like to arrange a telephone call so that you and I can speak in person. Is there a time that works for you during office hours (9-5) here in ******?