帮你简单改了下，有些语法和时态上的小错误。student cadre是中国特色，老美是根本是看不懂的，student leader好得多。industial是工业的，industrious才是勤奋的。别太看重推荐信，老外都懂，中国的推荐信都是假的，除非你找到特别牛的人给你写（比如国际知名的教授）。

Dear Sir or Madam,

I am very pleased to recommend a promising student, Ruihan Ma, for admission to your graduate program in Electrical Engineering.

I have known her since she enrolled in my course in “Digital Electronic Technique” in 2009. She was very conscientious and did a good job in every aspect of this class. She had extremely active performance in my class and was keenly interested in discussing with me after class about the Digital Electronic knowledge I introduced in the classroom. All of those mentioned above deeply impressed me. Furthermore, she has a perceptive mind and a very good understanding about the application of electronic technologies in the industry. Once I taught about the multivibrator circuit structure in my class, many students could not understand how to use its different forms in various situations. Yet Ms. ma comprehended the key points of this problem rapidly and helped other students solve this problem.

More importantly, as Ruihan is also a student leader in her class, she showed her initiative to help those who weren’t able to attend the class or couldn’t grasp the key of this class. I had witnessed her well-organized content about the class we had. In the content, she not only recorded many details I mentioned in the class, but also summarized them under a set of knowledge frames. I believe her efforts to make such summaries both helped consolidate her own knowledge acquisition and contributed to the whole class in their preparation for the course paper. I could perceive from her coursework conclusion paper that Ruihan was able to draw reference from previous knowledge and synthesize them into independent thinking of her own to explore some new topics about the technology application in some industries.

To conclude, Ruihan gave me a deep impression as an active and industrious student who has special learning aptitude in academic study. She is also a passionate leader and organizer of student activities who exhibits continuous zest to contribute to her community. Based on her notable performance, I believe Ruihan will achieve higher academic goal she sets for herself through advanced professional training in your program, and thus I strongly recommend her for admission. Your favorable consideration will be appreciated. Should further information be required, I am most willing to provide assistance.

Truly,