Pages won't open after unexpected shut down
I'd try clearing the saved state files.

From Finder:  


 Cmd ⌘   N   
 Cmd ⌘   Shift ⇧     G      
Copy/paste ~/Library/Saved Application State


Find the folder com.apple.iWork.Pages.savedState and delete the contents not the folder itself, as it's an alias.
That should give Pages a fresh start.