Study for 40-45 minutes every day. According to the national intelligent education platform for primary and secondary schools, basically a "class hour" is 40~50 minutes and 45 minutes in schools, but in social institutions it generally refers to training institutions, and a "class hour" is one to two hours. In addition, the unit of measurement of education and training time related to "class hours" means that learning time is based on the number of class hours. 1 credit = 18 class hours. Each credit is equal to 40 to 45 minutes of class hours per week in a semester, and how to calculate classroom learning and meet the specified quality requirements. From the point of view of class hours alone, 1 credit = 18 class hours, for the academic year credit system, the upper and lower limits of students' academic performance in each semester are stipulated.