[问题/Issue] 章节X.X：chapter5.1.2在线教材数据编写有误

[gangrammer]

1. 遇到问题的章节 / Affected Chapter

chapter5.1.2

2. 具体问题描述 / Problem Description

在线教材数据编写有误

3. 问题重现材料 / Reproduction Materials

确认事项 / Verification

• 此问题未在过往Issue中被报告过 / This issue hasn't been reported before