I know you said it was missing a line but here's what I think looking at it:
Explanation:
-What beliefs were common during this period that make the appearance of a ghost believable to the audience?
-What major political events occurred that the audience can compare to the politics in the scene
Shakespeare language can be sooo difficult to understand. If you haven't already, check out Sparknotes.com, you can pick which Shakespeare play (like Hamlet) and it translates his words into modern language. I hope this helps a little. Good luck!