Countable nouns are for things we can count
Examples: dog, horse, man, shop, idea.
They usually have a singular and plural form.
Examples: two dogs, ten horses, a man, six men, the shops, a few ideas.
Uncountable nouns are for the things that we cannot count
Examples: tea, sugar, water, air, rice.
They are often the names for abstract ideas or qualities.
Examples: knowledge, beauty, anger, fear, love.
Nota :
They are used with a singular verb. They usually do not have a plural form.
We cannot say : sugars, angers, knowledges.
Examples of common uncountable nouns
We cannot use a/an with these nouns
money, furniture, happiness, sadness, research, evidence, safety, beauty, knowledge
To express a quantity of one of these nouns, use a word or expression like
some, a lot of, a piece of, a bit of, a great deal of...
Examples
There has been a lot of research into the causes of this disease.
He gave me a great deal of advice before my interview.
They've got a lot of furniture.