What is the significance of college students going back to their alma mater in high school to preach?

Personally, I think it is more meaningful to go back, at least in college. Otherwise, I really didn't go back to find the sense of existence that was seriously lacking in the university. I have a good university life, I have a good impression on the university, and I really have deep feelings for my alma mater, so go back when you go back. But my personal experience is that, in fact, a large number of them are really happy in college, have realized their own value or are on the way to realization. The holiday is really busy. They have to do projects, practice, read books and play, and have no time to go back and do such things. Children and grandchildren have children and grandchildren? That's probably how I feel in my own words. Anyway, the college entrance examination and choosing a school are your own business. I observed my own life. If I really care, I will always try to collect information. In fact, the effective information that can be transmitted at the preaching site is limited. After all, it is still a serious occasion, and there will always be objective restrictions. As you said, time is precious.