www.airquiz.com is a useful site to test your knowledge as it has different questions to the confuser and makes sure you know your stuff!
If you can get 85-90% in both the confuser and airquiz, you are on track for a pass.
There are no shortcuts to any subject but these quizes highlight weak areas of your learning. You are best to re-read the whole section relating to your failed topic in the Air Law book.
Good luck!!!