Generally, these nouns cannot be pluralized. The waters of the Atlantic are much warmer this time of year. The Dutch are famous for their cheeses . The spring rains came early. It is appropriate to precede these nouns with a definite or indefinite article.
Poetry is beautiful.
Sugar is sweet. Experience is the best teacher. These nouns can be preceded by some, any, enough, this, that , and much . Because they are not countable, these nouns cannot be preceded by these, those, every, each, either, and neither . In fact, many of them cannot be.