After reading the subject once I printed out questions from a question bank and for each qestion I looked in the book to find out more about why the answer is the right one. It works realy well for me, and I can use the notes I made about the qestion to brush up, instead of the book. Of course some times it is good to go back and read more about the subject.
CBT with a search function is a good compliment to the some-times-not-so-easy-to-find-the-answer-in ATPL books.
D.