* They refer to general categories or types of people, places, things, or ideas. They don't name specific individuals or locations. For example, "dog" refers to any canine, while "Fido" is a specific dog's name.
* They are not capitalized unless they are the first word in a sentence or part of a proper noun. For example, "city" is a common noun, but "London" is a proper noun and is capitalized.
* They can be singular or plural. "Chair" is singular, while "chairs" is plural.
* They can be modified by adjectives. For example, "red chair," "big city," "delicious cake."
Here's an example of how to distinguish between common and proper nouns:
* Common noun: dog (refers to any canine)
* Proper noun: Rover (refers to a specific dog)
Common nouns are the building blocks of language, providing a way to talk about general concepts and ideas in a clear and concise way.