It is very hard. It's hard enough to be selected as an intern in Korea. It is hard for trainees to get the opportunity to go to Korea, so the competition between them will be more intense. Most companies have elimination system, which allows students to train in teams. The contents of the training mainly include: "vocal music, dance, body building, foreign languages, etc." Of course, physical exercise is essential, and even girls should lift iron every day. Of course, the most difficult thing is not the body, but the long-term depressed psychological state. Because it is the elimination system, this means that if you don't train hard and catch up hard, the opportunity will leave you sooner or later. The biggest fear of being a trainee is that you can't see yourself. You can make a debut if you practice well, and you can practice forever if you don't practice well. Moreover, due to the rise of the idol market in the past two years, many young people think that this is a way for them to harvest flowers and applause, which makes the competition in this industry more and more fierce. It's like crossing a wooden bridge with thousands of horses. Students who can come out must have experienced great hardships and suffered great psychological pressure.