Suppose I ask a question and someone gives me an answer. I partially understand it but not completely. Is there an idiom to say that you have understood something partially/ not completely?
I can say "I haven't got a firm grasp of it (the subject being discussed)", but I vaguely remember an idiom/expression that was in the form of "I still ...." and didn't have a negative word like not. Is there any other idiom or idiomatic expression to say that?