When you are talking about two or more things or people you have to make the count nouns plural.
You often make nouns plural by adding S at the end.
A boy boys
A girl girls
A taxi taxis
A teacher teachers
A book books
An uncle uncles
A river rivers
An elephant elephants
If the nouns end in s, ss, ch, sh or x, you make the plural by adding es.
If the last letter of noun is Y, you make the plural by changing the Y to I and adding es at the end.
If a noun ends in F you often make the plural by changing the f to v and adding ES at the end.
And with some nouns that end in O you make the plural by adding es.
But if there is a vowel before the Y you make the plural by just adding S at the end.
The plural form of some nouns is different from the singular form in other ways
The plural form of some nouns is that same has the singular form.
Some nouns always plural