how to enable workflow submodules in Modules administration page I am a very beginner to Drupal. In order to understand how Drupal-Workflow works, I try to install Workflow Module into my site. Following the installation guide on Drupal Documentation, i place the entire workflow directory into your Drupal modules directory, but when i go to the Modules administration page,  and try to enable the following workflow submodules, i get into the trouble, like this, i couldn't check the submodules. So, who can give me a hand, appreciate enough！
This page has suggested you the reason. You didn't install Entity module, you can get this module on Entity cache module.
This module has no user interface, if you enable it, entities will start being cached, if you disable it, they'll stop.