Why are hair and rice uncountable

Why are hair and rice uncountable

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There's a lot of hair. It's countless
There is also a lot of rice, countless

Onion is a countable and uncountable noun, but when is it countable and when is it uncountable?
This is a matter of English grammar~

Just like egg
When you count one by one, it's countable
When you put it on the plate, it's uncountable

What's the difference between countable nouns and uncountable nouns
In English, what are uncountable nouns and countable 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

Is fish a countable noun or an uncountable noun
The fish can't live in the death sea?
No, it can't. or no, they can't
Who knows? I'm in a hurry to know. Thank you!

They have a large collection of fish. Fish are cold-blooded

This is my sister
fast

These are my sisters.

My father and my mother are___ teachers.
A.both B.all
C.too D.whole

A both
My father and mother are both teachers

My father and mother are both teachers

Both of my parents are teachers.

My father and mother are teachers._____ are busy

They

His father and mother are teachers_____ Teachers

His parents are teachers.

This is my mother and this is my father
That is my father

they are my parents.