A friend of mine recently had a test during one of her English classes and there was a task to choose the correct word that best fits the sentence: "Few of the students knew ___ of the answers". And the options were: no, none, any, some.
I, personally, never learned grammar in a formal way, so I always do such tasks intuitively. In my opinion, both options none and some fit the sentence, but they both make the meaning of the sentence different. My friend also thought in the same way and chose the option "none", because, as she said, "it felt more optimistic".
However, it turned out to be wrong, and she asked her teacher about it, and she replied that the correct option was any. She said, quote,
'few' is negative, and you cannot use double negation in a sentence.
So the correct way to say that turned out to be "Few of the students knew any of the answers." But neither I, nor my friend do not understand the meaning of this sentence. Does it mean something like "a little amount of students knew at least anything"? Plus, I do understand that double negation is a big no in English, but I just cannot comprehend how can "few" be negative and what this "correct" sentence really means.
I understand that this question is not really quite specific, but I would be really grateful is somebody could explain me why my options were wrong and what does the correct sentence really mean. Thanks a lot in advance!