Start by naming any country that France borders. Then name any country that borders any of those countries. Then keep going until there are no more countries left to name.
For #8, do you mean what language other than German is the most common *natively* spoken? I was obviously suspicious that less than 1.8% of Germans spoke English, and sure enough – 56% of them do. You should probably change the wording, since as the question stands now, English is definitely the correct answer. ~~ • ~~ Great quiz, by the way; I'm sorry it wasn't featured!
Number 19 is kind of tricky question - maybe not good for this. It gave black - red - yellow for first option for me so i did not even read the rest because first was "right". Otherwise good quiz.