If you can't remember the time, it is very useful to recite the summary poem about the approximate time of that period of history, and I still remember it clearly! As for the specific time, the general exam will not be too strict! Just write, such as the Northern Song Dynasty and the Late Tang Dynasty. Hongwu XX and Wanli XX, I don't really want you to be specific.
If the characters can't remember, they will take out a small notebook to classify. For example, it is divided into emperors, courtiers, medicine (remember some famous ones such as Bian Que and Sun Simiao), mathematics and so on. You have to explore the specific methods yourself, everyone has their own set.
Finally, I wish you like history!