单词拼写。

增加：在缺词处加一个漏字符号（∧），并在其下面写出该加的词。

删除：把多余的词用斜线（\）划掉。

修改：在错的词下划一横线，并在该词下面写出修改后的词。

注意：1）每处错误及其修改均仅限一词；

2）只允许修改10处，多者（从第11处起）不计分。

Dear Sir or Madam

    I've learned from the newspaper dial my company is looking for a clerk. I'm very interesting in the job and I'd like to apply for at the position.

    First of all， allow me introduce myself. I have just graduated from senior high school and take the College Entrance Examination. I want to find an part - time job in the summer. I'm 18 years old and have a good knowledge of English, especially in terms at speaking and listening. In fact, I won the first prize in the English speech competition hold in our school last year. Besides, I'm quite easy - going and therefore very popular among my classmate.

    I sincere hope you can give me a chance. I'm looking forward to your early reply.

Yours,

Li Hua

已知$x\in \left(0,+\infty \right)$，观察下列式子：$x+\frac{1}{x}\ge 2$，$x+\frac{4}{x^2}=\frac{x}{2}+\frac{x}{2}+\frac{4}{x^2}\ge 3$，，类比有$x+\frac{a}{x^n}\ge n+1\left(n\in N^{*}\right)$，则a是（   ）