题目内容：

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．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．

Last month our class organized a hiking along the Chaobai River，which run through Hebei， Beijing and Tianjin． Much to my disappoint， I found the river was serious polluted． At that moment， I was determined to do what I could protect it． First， under my teacher's help， I used the equipments from the school lab to test the quality of the river water． But then，I used the data I had collected it to analyze the pollution of the water． Finally，I write a report on the pollution of the river to the local government． I also gave a presentation in class where I suggested that we must make small changes to protect our water resources．