自己写的一封推荐信草稿，求大神来观摩一下，批评指正

I came to know XXX in last year when he enrolled in my class on Computer Organization and Design.(We used “Computer Organization and Design The Hardware/Software Interface Fourth Edition” as the textbook.) In the class he was one of the most outstanding students. There is an important factor that should be included that the class is one of the best classes in our university because several examinations selected 19 students who constituted the class from 800 candidates three years ago. So it is not easy to be outstanding in the class.
　　Through teaching and informal consultation, I had chances to get to know his academic potentials and ideals. Mr.XX contacted every week and the conversations between us showed his logical and analytical thoughts. Moreover, in group discussion, he was always the revolutionist who could bring innovative ideas to his group mates. In my opinion he can be reliably graded as one of the best undergraduates here in 653 grade students with majors in our department. At that time, I could see that he paid more than 3 hours every day in my classes. I had learnt that he had designed a five-stage pipeline CPU when he was attending my lesions. Apparently, he is a very bright student and has systematic knowledge of the construction of computer. It is clearly that he has special interests and enjoyment in mathematics and computer science, which can be further developed.
It is because of the potentials of students in the class, I taught them more things than I designed at first. At the end of the semester Mr.XX earned a high grade of 87, which should be very brilliant according to our grading system since the tests that I gave to them were much more difficult and comprehensive than which I provided to students in other classes. From our talks, I found that he attended more mathematical lectures than normal students major in computer science and knew how to apply math to computer science. I think it is good for a student major in computer science to learn math since math is the foundation of every subject and many theories of computer need the help of math.
　　In view of his previous achievements in this College, I am firmly convinced that Mr. xX will make a successful graduate student. Your favorable consideration of his admission will be highly appreciated.　　Please do not hesitate to contact me if I can be of further assistance.

当你在标题上加入“大神”的字样的同时，也就堵上了和我一样的其他人的嘴。

请大神……………………观摩………………

有几处语法错误啊，还有少逗号啊。。我不是大神，但是一字一句看了一遍。several examinations selected 19 students还是19 students including Mr.XX from 800 candidates were selected by several examinations. ****Mr. XX contact (whom) every week.****attending my lessons(typo)****major in 还是majoring in?(appeared twice)****我也在愁推荐信，参考一下楼主的，顺便提点建议，不一定正确