What are the short names of students in the experience class?

Students in the experience class are generally called "experience students", and can also be referred to as "experiencers" and "experiencers" for short. Experience class means that students can attend one or several audition classes before learning a certain course, and learn about the course content, teaching methods, teachers' level, etc., so as to better choose the course. Therefore, students who experience the course are usually students who have not registered for the course. They can learn about the characteristics, difficulties and suitable people of the course by attending the audition course, so as to better choose whether to attend the course or not. In some online education platforms, there is also the title of "test student", which has the same meaning as "experience student". In short, students who experience the course can be abbreviated by many names, but the meaning is the same, that is, students who have not signed up for the course but have participated in the audition course.