For example, the imperial examination system in Ming Dynasty (imperial examination system) was an ancient examination system for selecting officials in China, which was mainly divided into three stages: after having obtained the provincial examination, after having been recruited from the middle school, and after palace examination. In the eighth grade history notes, braces are usually used to indicate comments, explanations, supplementary explanations, etc. Generally, put brackets around things that need to be explained. Generally speaking, there needs to be a space between the braces and the comment text.