Hi. I am not the original poster, but I am having the same problem even after trying all the steps above. Whenever I pause the video, the screen goes white, preventing me from reading the stimulus and answers. I am on a Mac.

A conditional relationship is when one set is completely inside another set, such as a subset inside a superset. The example they always give is "If Jedi, then Force" where Jedi is the subset, and it is completely encapsulated by the superset Force. An intersection is when 2 sets overlap but not completely. Think of a Venn diagram - we are only talking about the middle part where both sets overlap.