Solution:
1. First, in "Slide Show", click Custom Slide Show, and you can see how many slides are missing.
2. Click the "Set Slide Show" option in Slide Show.
3. You can open the dialog box for setting slide show, and you can look back at "Custom Show 1" under the column of "Slide Show".
4. Then change the originally selected "Custom Show" option to "Answer All" option, and the slide show page will be displayed completely.