改错题。

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短文。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：在错的词下画一横线，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。

    A city, whether big and small, should be clean. Only when we live in a clean city we live a happy life. As we know, a clean city, that disease may be reduced and people's health may be better, are good both for our mind and body. No one believes people lived in a dirty city with waste everywhere can live happy. However, for more and more people moved into our city, it is not easy to keep our city clean. Beside, some factories will pour waste into the air, the river and onto the ground, making it is hard to keep our city clean. To make our city the better place to live in, we still have a lot to do.