For Germany, I reakon something on either the great depression or versailles/WW1 i.e. "To what extent was Germany's defeat in WW1 (or the treaty of Versailles) responsible for the fall of the Weimar government." or "To what extent did the Great depression contribute to the downfall of Weimar democracy". I reakon for Nazi Germany they could ask something about social life maybe or racial policy.
For Conflict in Europe, I reakon D-Day like "Assess the view that D-Day was the most critical turning point of the war in Europe." Although I think its unlikely, the BOS could be particularly cruel and ask about the russian counter-offensives, the non-aggression pact or Nuremburg.