It won't be so difficult to maintain that kind of ordinary friendship, because now the internet is developed, and many friendships are "favorite friends", so you can pay more attention to the dynamics of friends, praise them, comment on them, and share your life occasionally in private, so you can maintain friendship. Moreover, the winter and summer vacations in universities are generally long, so it is also a leisure way to get together with friends from three to five and share their new university life.
But understand that we can't control others and never change as before. What will never change in this world is change. As friends, we must respect and accept the changes of our friends. For example, the other party is no longer single, and the other party has announced that he has been single. Most people may think about things after they go to college. Our views may be different, but as friends, respect and constant concern are the most important. Remember not to blame your friends for some changes. After all, different environments will make different people.
The final conclusion is, make good use of the network to connect feelings, and don't forget the offline party, while maintaining respect.