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处错误，每句中最多有两处，每处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（^），并在其下面写出该加的词。

删除：把多余的词用斜线（\）划掉。

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。

My dream school starts at 8:30 a.m. and ends at 3:30 p.m. They are three lessons in the morning and two in the afternoon .We didn’t need to do so many homework .Therefore , we have more time with after-school activities .For example , we can do reading for one and a half hour and play sports for one hour every day .

My dream school look like a big garden .There are all kinds of the flowers and trees around the classroom buildings .We can lie on the grass for a rest , or sat by the lake listening music .The teachers here are kind and helpfully .They are not only our teachers but also our friends .

对某水源检测结果显示，氨氮、亚硝酸盐氮和硝酸盐氮都较高。试对该水体的污染情况进行评价。