when she's asked for explanations or to clarify a concept, she just repeats what she's said before in the exact same words

UGH. My sympathies. Coincidentally, my high school Chemistry teacher had this exact same problem! It was so bad that I would definitely have failed that subject if my dad hadn't taken it upon himself to teach me directly from the textbook using his own analogies to explain the basic concepts. I managed to scrape by with a passing grade, but am still bitter about what a terrible teacher she was. :/