請幫幫手, 睇下有無要改, 謝謝

I have over six years working experience in <field> and joined the team as a clerical assistant in XXXX. In the past few years, I assisted and maintained files in daily operation. I have comprehensive knowledge to meet the job requirements on both aspects of operation and the business. I proactively reviewed daily workload so as to streamline workflow to the team. With my strong PC knowledge, I helped teammates to resolve PC problems and computerized work flow proactively. I am confident that my extensive work experience and solid work ethic have well prepared me to take up the senior position and make valuable contributions to your workforce within the company. I look forward to hearing from you. Thank you for your time and consideration.

Comments:
(1) I worked as a clerical assistant since 2005. I joined the team as a clerical assistant in 2005.
(2) ~ assisted and maintained what ? (I put in files, may be something else)
(3) ~ comprehensive knowledge instead of sufficient knowledge. Sufficient knowledge gives the impression that you have just enough knowledge.
(4) Besides extensive work experience, I add solid work ethic.
(5) ~ valuable contributions, not valuation contributions.
(6) The last two sentences conclude the paragraph.

Well, I don’t like to change too much of your wording.盡量保持你原意. Hope my criticism is a constructive one. All the very best!

假如不更改全的寫法，只是改正字詞和文法的錯誤，請看粗體字，[]表示原有字刪除：
I have over 6 years working experience in <field> and joined the team as a clerical assistant since XXXX[假如xxxx是2005便是多餘]. In past few years, I assisted and maintained the team in daily operation. I have sufficient knowledge to meet the job requirements on both operation and the business. I [] proactively reviewed daily jobs so as to streamline workflow of the team. With my strong PC knowledge, I helped teammates to resolve PC problems and computerized work flow[]. I am confident that my work experiences have well prepared me to take up the senior position and make valuable contributions to the company and the team.

但是如我寫會如下：
I have over 6 years working experience as a clerical assistant in <field>. In the past few years assisting and maintaining the daily operation to streamline work flow of the team through computerization, I have had sufficient knowledge to manage the people and business of the team. Combining strong PC knowledge and work experience, I am prepared to take on the senior position and contributes to the bottom line of the business.
註：the team這名詞較為難明為那一類別，最好加上/改為特定的組別，如sales team/operation team/service team???

如果係我寫的話，我會咁樣寫：
"I have been working as a clerical assistant in for six years. My responsibility is to assist the (Manager or Supervisor) maintaining daily operation of our team. I continuously review and propose the enhancement of the workflow in order to improve our efficiency. I'm familar with (PC system, programs or some special programs) so that I can solve the problems raised by our teammates. I think my knowledge and experience can fulfil the job requirement stated in the advertisement. I'm prepared to take up the position of (post) and try my utmost to contribute to your company.

Please kindly consider my application. "