“The difficult we do immediately; the impossible takes a little longer.” – US Army Combat Engineers saying, original quote credited to many different people
If you're having trouble with an assignment, start by completing just the questions that jump out as easy enough to answer. Once you get through all of those questions that you can comfortably handle, go back to the beginning and take another look at the ones you skipped.
Complete any that don't look quite as bad on the second pass, those that maybe you had to do a little more digging to find but you at least have an idea where to start looking. Go back again and try to find a few more you can answer, until you're left with just the questions you don’t know how to start or that you can start but not finish.
Once you're down to that last group of questions, send an email for your instructor! She'll be happy to help you get back on track with those "impossible" questions.