Possible version:

Dear Sir/ Madam,  

I learned from the website that your company needs a part-time English editor. I believe I am fully qualified for the job.

My name is Li Hua, and I am quite good at English. I like reading English articles in my spare time, which benefits me a lot in my English study. Besides, I have had several part-time jobs as an English tutor before and taken part in the English writing competition in our city. What’s more, I am a team player and get along well with other people. 

I hope you can give me a chance. I am looking forward to your reply.                                                              

                                                              Yours sincerely,

                                                                    Li Hua 

阅卷老师注意：

   高考作文字数在80-120字左右，低于80或多于120字都要被扣分。所以，务必请高三的老师在平常教学中注意字数的控制！如果字数不好控制，可以用句子来控制，长句多的8-9句话，句子短的9-10句话左右，大家可以灵活处理。