假定英语课上老师要求同桌之间交换修改作文，请你修改你同桌写的以下作文。文中共有10处语言错误，每句中最多有两处。没出错误仅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. 每处错误以及修改均仅限一词。
2. 只允许修改10处，多者（从第11处起）不计分。
My brother Donald didn’t do well in math. When the day of the exam comes, Donald sat next to Brian, which was always good at math. Donald careful copied Brian’s answers. At end of the exam, the teacher collected the papers and graded it. Then she decided to give a prize to the student who got the high grade. But it was a bit of difficult for her to make a decision, because Donald and Brian got the same grade. The teacher thought about that and made on her mind to give the prize to Brian. Donald said it was unfair. “That’s true,” the teacher said. “Therefore, Brian’s answer to Question 18 was ‘I don’t know’. Your was ‘Neither do I’.”