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（∧），并在其下面写上该加的词。
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. 每次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 will cost this summer holiday in the countryside. Although the city is
modern, but there are still some problems, such as air pollution and noisy. In
the countryside I can enjoy a comfortable and quietly life. Where, the air
is fresh and the water is clean. Trees are green and birds are singing. I can go boating, fishing and swimming in the lake. I can also climb the hills. Both of these will interesting and good for your health. Above all, I can learn more about the nature. So I want to go to the countryside for a change. Now, I am looking forward to leave.