Add a Caption To an Existing Slide

## Can you think of a better caption?
Each slide can have more than one caption. Check out the current slide show and add a caption (or two).
If you need help, check out the Appendix in the training manual.

检查当前幻灯片放映，确定一个适合添加图注的现有幻灯片；如需指导，请参考培训手册中的附录。为该幻灯片添加一个或两个图注，并确认它们在幻灯片放映中正确显示。

由索引模型根据 Issue 内容生成。