15. There is 1) few 2) little 3) many 4) the fewest in this bottle.

The correct choice here is "little." You would say, "There is little in this bottle," when referring to an uncountable noun, such as liquid. Using "few" would imply a countable noun, which doesn't fit the context of the sentence. Common mistakes with "few" and "little" often involve confusing countable versus uncountable nouns. Remember, "few" is for plural nouns, suggesting a small number ("few friends"), while "little" is used for singular mass nouns to indicate a small quantity ("little sugar"). Keeping this distinction in mind can help avoid mix-ups!