假定英语课上老师要求同桌之间交换修改作文，请你修改同桌写的以下作文。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。
Square dancing bus been more and more popular with the elderly as their living conditions improve, Most people thought it can help people take regularly exercise and strengthen their fitness. Besides, it provides people more chances to take activity outdoors. However, some people argue that the music is very noisy, that disturbs the surrounding citizens' normal life. Also, be exposed to such loud noise may do a harm to their health in the long run.
In my opinion, square dancing is a good form of exercise, so dancers should take our neighbors' needs into consideration. If they choose a right time and turn down the music, it will cause fewer trouble for others.
常见遗传病中属于染色体变异的是