以下是我個人建議，僅供參考~
首先我覺得這篇文章寫得略過簡單，沒有特別出彩的地方，有點像四級考試作文~
然後有些地方我覺得語法不對，寫得有點中國式英語
第壹句：I am writing to you to recommend a movie for you which shows an Chinese assassin in Qin Dynasty.
The name of the movie is hero,you may be confuse about why an assassin is a hero.
but they do not use it unlimited 這裏unlimited應改為unlimitedly~副詞修飾動詞。
because they know,with great power comes great responsibility.
可以改為：the more power they use, the more resposibility they shuold pay.
The chief actor of this movie is acted by Li Jet ，這句actor應改為role.
In this movie,you would know a truth that a greet knight,for the country and for the people,it is the essence of the Chinese Xia culture.這句中it is the essence中is應去掉，不然壹個句子有2個主語了。
he has kung fu ，這個我感覺不應該用has,但我也不知道用什麽好
暫時就這些了，希望對妳有幫助~