Countable nouns are for things we can count using numbers. They have a
singular and a plural form. The singular form can use the determiner "a"
or "an". If you want to ask about the quantity of a countable noun, you
ask "How many?" combined with the plural countable noun.
She has three dogs;
I own a house;
I would like two books please;
How many friends do you have?Uncountable nouns are for the things that we cannot count with numbers.
They may be the names for abstract ideas or qualities or for physical
objects that are too small or too amorphous to be counted (liquids,
powders, gases, etc.). Uncountable nouns are used with a singular verb.
They usually do not have a plural form.
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;How much rice do you want?