Are you having difficulty reading some of the primary source readings/worksheets?
They are meant to be challenging. But here's a way to overcome the difficult vocabulary: You may want to read them with your iPad or Kindle, as the iPad/Kindle allows you to view the definition of any word by selecting the word, and holding your finger over it. On a Kindle, the definition pops up automatically, and on an iPad you simply choose "define" from the options that pop up.