假如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。每处错误仅涉及一个单词的增加、删除或修改。
增加：在缺词处加一个漏词符号（∧），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：在错的词下面划一横线，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。
When we play football on our school's football field, we have got be very careful. That's because of there is an ancient tree growing in a middle of it. Our school is surround by many historical building. When we decided to turn the only available space into a football field, we find the tree had to be removed. We asked for permission to have it removed anywhere else, and it was too risky because the tree is considered as a national treasure. Final, we decided to build the field around it. I consider the tree as a great symbol of our school.
