The local environment is different ~ ~ ~ especially in the north. In some places in the north, it is particularly cold in winter, and it snows in some places. In this cold weather, socks will be worn at home ~ Then it will be dirty to wear socks at home. It is impossible to do hygiene every day in winter in the north, and it is not easy to dry after mopping the floor ... If it is in the south, the weather is not so cold and there is no need to wear socks at home ... It is also possible that this girl does not like hygiene herself. It's normal to wear only one pair of shoes every day ~ ~ It's normal for students' socks to be dirty, and it's easy to get dirty when they run for a step and do strenuous exercise in sports class ~ Anyway, there are many dirty factors ~ ~ ~ What are you doing to correct this problem? Dirty is normal, just like white clothes. Sometimes it is difficult to clean clothes when they are dirty or dyed, and it is even more difficult to change them back to white like new ones. ...