58a Use count and noncount nouns appropriately.
Look at the following sentences:
Research shows that this chemical can be dangerous.
Studies show that this chemical can be dangerous.
Studies is a count noun, and research is a noncount noun. Count nouns (also called countable nouns) refer to separate individuals or things that you can count: a study, a doctor, a book, a tree; studies, doctors, three books, ten trees. Noncount nouns (also called mass nouns or uncountable nouns) refer to masses or collections without distinctly separate parts: research, milk, ice, blood, grass. You cannot count noncount nouns unless you use a quantifier: one blade of grass, two glasses of milk, three pints of blood.
Count and noncount nouns also differ in their use of plural forms. Count nouns generally have singular and plural forms: study, studies. Noncount nouns generally have only a singular form: research.
| COUNT | NONCOUNT |
| facts | information |
| suggestions | advice |
| people (plural of person) | humanity |
| tables, chairs, beds | furniture |
| letters | |
| pebbles | gravel |
| beans | rice |
Some nouns can be either count or noncount, depending on the meaning.
| COUNT | Before there were video games, children played with marbles. |
| NONCOUNT | The floor of the palace was made of marble. |
When you learn a noun in English, it is useful to know whether it is count, noncount, or both. Many dictionaries provide this information.