new at this

Im new at this just graduated this summer I had my first CNA test a couple weeks ago passed EVERYTHING except BP I have my second test in 24 hours and I still cant hear a thing Ive practiced on more then one person with more then one Stethoscope I need help please I cant fail this test a second time I cant bring my own Stethoscope into the test and the one they provide you with is the double headed one the pt in laying in bed I need help