You can't explain anything from what you see. First, it is possible that people do have mines at home, but private education is really better than self-study or other channels, so it is better and more beautiful to do it directly. The second family may scrimp and save at ordinary times, but in order to better themselves and have a strong sense of fitness, it is not impossible to use the money saved in this place. The third possibility is that fitness is brought by people around you. It's said that it's also good to teach privately before doing homework, and see if the effect is good. Therefore, if you want to see a person in all directions, you can't just look at one place or just watch others make cards. Maybe others come back and forth several times or you have never seen it before.