This is the 2323rd most frequent Chinese word.
上課
Attend class; have a lesson.
In this sentence, '上課' is used to indicate the action of attending classes.
学生们早上八点开始上课。
The students start attending classes at 8 AM.
Here, '上課' is used to describe the event of conducting a session for learning.
今天我们要上课学习新知识。
Today, we are going to have classes to learn new knowledge.
In this example, '上課' is used to refer to the upcoming commencement of a class.