You can add more depth by considering your purpose. How will knowing, how that works, satisfy your purpose to...? ("understand" the principle so that I can pass the test on the topic is a perfectly valid answer; also to "understand" it so that I can see if I can apply it to my purpose is a valid consideration).
Just considering your purpose also helps to form questions and even if you can't form ideal questions... you mind being aware of your purpose is going to point you to information that you need to know or will want to know consciously.
Alex
