Just because the equipment in the gym is occupied doesn't mean everyone is practicing. Some people just sit on the equipment and have a rest. They don't study at all, or have already practiced. When their physical strength recovers, you can talk to them at this time. You say, ok, I'll sit in a group, and then you can change. At this time, these people usually let you do it. After all, gym resources are public resources, and people who apply for fitness cards have the conditions to enjoy them. This situation is easier to negotiate. As long as you are willing to talk and communicate with others, you will certainly find idle resources.