Interview Prep Advice

So I have begun the task of preparing for investment banking interviews and I feel as if I have run into a roadblock. I have been using the BIWS interview guide and it has been great so far. I have gone through the basic accounting section and feel that I can run through the three statements and be able to see how certain adjustments affect the three statements. However, there are questions on this forum and online that seem to come from left field and I have no idea how to answer them. I feel that I can’t answer all these questions and master all the material needed to be able to answer them, am I just screwed when interview time comes, if it comes? What methods did you use to prepare and in interviews how many of the questions did you just have no idea how to answer? I want to be as prepared as possible, but there comes a point where between classes, a sport, and a job that learning all this info to answer EVERY question just becomes impossible.