food既是可数名词又是不可数名词。
food 仅仅指"食物、食品"的时候是不可数名词，作不可数名词讲时量词用 a little，如：There is a little food here.
food 强调食物种类的时候作可数名词，作可数名词讲时量词可用 a few，如：There are not a few of fresh foods on the shelves.
