What we have learned now is not necessarily correct. But I think the purpose of studying history is not only to understand some basic common sense events, but more importantly, to learn how to look at the present world through history.

It is not impossible that China once occupied other countries. The vast territory of the Yuan Dynasty must have been occupied. However, this kind of thing should not be too much. After all, our deeply rooted Confucianism does not advocate aggression.

If you really want to know the real history, you can look at the history books published by non-mainland writers such as Taiwan Province Province, which may be helpful to you.