Ask her about the topic. Learn a little yourself and show a genuine interest then ask for her help understanding it. This creates salience in the learning for her and also shifts her from arbitrary retention to learning to explain to you, so the mental structures are much more dynamic.

I would also recommend finding interesting things that are on the other side of understanding that material. For example, what is in the next unit? What cool things will learning this stuff unlock? It is not always the best strategy especially at the start of the unit, but as you get towards the end of the unit it can help bring the focus back to getting through the exams.