In winter, students in university dormitories don't close the windows. In winter, they should also properly open the windows for ventilation to make the indoor air smooth. No matter every day of the year, the window should always be open, because according to Yuqin and these aspects, it is best to keep the air relatively ventilated, which is good for your health. So learning to protect yourself is an important factor, especially at that stage of this student's study.