What is the singular form of countable nouns in English sentences?

What is the singular form of countable nouns in English sentences?

Nouns in English can be divided into countable nouns and uncountable nouns
The countable nouns refer to the nouns that can be counted clearly
Uncountable nouns are nouns whose number is not clear
Uncountable nouns have only one form
But countable nouns have two forms, one is singular, the other is plural

How to distinguish countable nouns from uncountable nouns?

Countable nouns and uncountable nouns
English nouns can be divided into countable nouns and uncountable nouns. It is very important for us to judge whether a noun is countable or uncountable, because it involves whether to add an article before it, what kind of article to add, and the proper form of the word in the sentence
So, how to distinguish countable nouns from uncountable nouns?
Generally speaking, countable nouns can be divided into singular and plural. For example, nouns expressing people or things and collective nouns are generally countable. Sometimes, we can try to add a cardinal number word before the word to judge
A boy three boys some boys
A desk 40 desks 40 desks many desks
A film some films
A story two stories
A song some songs
An apple 9 apples 9 apples some apples
Police officer Chinese
Material nouns or abstract nouns are generally uncountable. Uncountable nouns have no difference between singular and plural, for example:
Water ice tea tea meat milk
Age time help help luck work
A few material nouns also have plural forms, but their meanings are different
Glass countable noun glasses
The water of a river or lake
By the way, some material nouns are also countable nouns, but their meanings are different
Material noun countable noun
Glass a glass
A paper; a paper
Wood a wood forest
Gold a gold
It seems that it is not difficult to learn countable nouns and uncountable nouns, but it is not easy to learn them well. There are many words that can be understood only by looking up a good dictionary. In addition, we should read and remember more when we read books. Only by accumulating more can we learn them well

How to distinguish countable nouns from uncountable nouns
I don't like to read long speeches if I can explain it more simply

Countable nouns have plural forms, such as an apple two apples a bag some bags
Uncountable nouns generally have no plural form, such as broccoli
There are also some words that can be used as countable nouns or uncountable nouns,
For example: ice cream, salad, chicken