Some final comments, about cover-letters.

     Cover-letters are very important.  Although they seem not to be used as much in P. R. China as in the USA (where they must accompany a resume, without fail; no cover letter, no interview), they will be in the future.  Due to the constantly changing business world, business habits, and there being many foreign companies in P. R. China, more and more companies will start requiring job-applicants to write a cover-letter. 
     Study the example here, but also look at the examples in the Internet, to see what others are doing.  Also, look at the “how to” books, and talk with the Human Resource people in various companies, to get their opinions.  However, what you finally write should be synthesized, over time, into a letter which is by you, and about you. 
     Your cover-letter must do these things : (a) It must be carefully developed over time, by you, and with input from your peer-reviewers; (b) It should be ready for instant presentation (with room for a few modifications) to the Human Resource people in some company, at once; (c) It should be easily adaptable, so it can be used in other job search situations; (d) It should be about you, and not “the crowd”; (e) It should evolve over time, as you too evolve professionally. 
     Please keep all the rough drafts you write, and write the date on each one.  In this way, you will have a “textual record” of your writing development; in later years, you can follow your progress as a writer.  This is important.  You will also have certain, obscure details about your life on paper.  This may sound strange to keep these things, but be warned!  There is always some future employer (usually government), who wants to know what you did, and when, and where, and with who, and so on....