Most of this should be review since you've already completed the Foundations HTML/CSS Lesson (Right??) but it's a good idea to make sure you've got it covered so you make sure you're starting from a strong base. It's impossible to separate HTML from CSS, so there will be some overlap before we get heavily into the CSS in later sections.
How is an HTML5 document structured?
What are elements/tags?
What are element attributes?
How do you link to external files?
When should you use IDs vs Classes?
What attributes are required by image and links for them to be effective and accessible?