假定英语课上老师要求同学们交换修改作文，请你修改你同桌写的以下作文。文中共有10处语言错误，每句最多有两处。错误涉及一个单词的增加、删除或修改。
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，并在该词下面写上修改后的词。
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。
I was reading an article in a book while I came across a word I didn't know. “Dad, what is the meaning of the word?” My dad, as he usual did after work, was watching his most favorite show. “You have the dictionary, don't you?” he shot back. He didn't even look up my face. I went back my room, and there on my study table is that dictionary. I looked it up and found it's exact meaning. Ten year have passed and I still use that dictionary, along with the lesson I received earlier in life from my old man: to be independent.
（铪），它的中子数是