This document discusses countable and uncountable nouns in English. It provides examples of plural nouns that end in s but remain singular in meaning, as well as nouns that are always singular. Collective nouns can be either singular or plural depending on context. Certain adjectives referring to groups use plural verbs. Proper usage of persons versus people is covered. Uncountable nouns are defined as those that cannot be used with a/an or in plural form. Finally, some nouns can be either countable or uncountable depending on whether they refer to a general concept or specific instance.