Class hours are the time unit of continuous teaching, that is, a class hour is the time occupied by a class. According to the convention, basically a school class lasts 40-50 minutes (mostly 45 minutes).

In China, a class in primary and secondary schools is generally 45 minutes, while that in colleges and universities is 50 minutes. The unit of measurement of education and training time related to class hours is class hours. Class hours refer to the learning time calculated by class hours. It is generally believed that both non-adult education and full-time university education are 40-minute classes.

There is no time difference between a class and a class, but a class indicates the number of courses and a class indicates the time of courses.

Arrangement of teaching hours in ordinary senior high schools:

Each class lasts 45 minutes, and there are 7 class hours every day. Students are in school five days a week and have 35 class hours a week. Due to the changes in the content, structure and setting of the new curriculum, the teaching mode of different modules in some disciplines is different, and ordinary high schools can make appropriate adjustments according to the actual situation.

In principle, all compulsory courses are arranged in Grade One, and elective courses are arranged in Grade Two and Grade Three. In the next semester of senior three, the school should ensure that every student has the necessary time for sports and health, art (or music and art) and other activities, and encourage students to continue to take certain courses according to their own interests and needs, and get certain credits.

In order to reduce the number of times students change classrooms, shorten the distance between classes and arrange teachers reasonably, some courses can be arranged for 90 minutes (that is, two classes are arranged continuously).