With comments on .pdf, it is possible to annotate while reading. This allows you to pick up your text with AF bookmarks, allowing you to reflect as a classreader on the points devised by yourself and others.

This would be particularly good with tablet reading of a shared .pdf…

More of this to come: use iannotate. https://play.google.com/store/apps/details?id=com.branchfire.iannotate&hl=en_GB

Use highlighter and the commenting tool.

Then, when using adobe .pdf reader, jump to comments to facilitate discussion.