It’s important to distinguish between countable and uncountable nouns in English because their usage is different in regards to both determiners and verbs.

Countable nouns

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.

Uncountable nouns

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.

We cannot use a/an with these nouns. To express a quantity of an uncountable noun, use a word or expression like some, a lot of, much, a bit of, a great deal of , or else use an exact measurement like a cup of, a bag of, 1kg of, 1L of, a handful of, a pinch of, an hour of, a day of. If you want to ask about the quantity of an uncountable noun, you ask “How much?”

Tricky spots

Some nouns are countable in other languages but uncountable in English. They must follow the rules for uncountable nouns. The most common ones are:
accommodation, advice, baggage, behavior, bread, furniture, information, luggage, news, progress, traffic, travel, trouble, weather, work

Be careful with the noun hair which is normally uncountable in English, so it is not used in the plural. It can be countable only when referring to individual hairs.

Pronouns replace nouns. A different pronoun is required depending on two elements: the noun being replaced and the function that noun has in the sentence. In English, pronouns only take the gender of the noun they replace in the 3rd person singular form. The 2nd person plural pronouns are identical to the 2nd person singular pronouns except for the reflexive pronoun.

Subject pronouns

Subject pronouns replace nouns that are the subject of their clause. In the 3rd person, subject pronouns are often used to avoid repetition of the subject’s name.

Object pronouns

Object pronouns are used to replace nouns that are the direct or indirect object of a clause.

Possessive adjectives (determiners)

Possessive adjectives are not pronouns, but rather determiners. It is useful to learn them at the same time as pronouns, however, because they are similar in form to the possessive pronouns. Possessive adjectives function as adjectives, so they appear before the noun they modify. They do not replace a noun as pronouns do.

Possessive pronouns

Possessive pronouns replace possessive nouns as either the subject or the object of a clause. Because the noun being replaced doesn’t appear in the sentence, it must be clear from the context.

Reflexive & intensive pronouns

Reflexive and intensive pronouns are the same set of words but they have different functions in a sentence.

Reflexive pronouns refer back to the subject of the clause because the subject of the action is also the direct or indirect object. Only certain types of verbs can be reflexive. You cannot remove a reflexive pronoun from a sentence because the remaining sentence would be grammatically incorrect.

Intensive pronouns emphasize the subject of a clause. They are not the object of the action. The intensive pronoun can always be removed from a sentence without changing the meaning significantly, although the emphasis on the subject will be removed. Intensive pronouns can be placed immediately after the subject of the clause, or at the end of the clause.

Indefinite pronouns