girl

dog

person

people

egg

children

banana

elephant

apple

aunt

hour

honest man

ugly man

when talking about someone or something for the first time

When talking about work or occupation, the indefinite article is generally used

Fixed collocation (a/an=one)

e.g.: The old fisherman had a cat. The cat was white.

e.g.: Has she returned the book?

e.g.: Please give me the key on the desk.

a. Before nouns indicating direction and orientation

b. Before a noun that is unique in the world

c. Before the names of rivers, oceans, lakes, islands, and mountains

d. Before proper nouns, proper nouns refer to state agencies, groups, classes, etc.

e. Before the noun of a musical instrument, it means playing

f. before certain adjectives, indicating a type of person or thing or some abstract concept

g. Before the plural form of a surname, it means the whole family or the couple with this surname.

h. Before the plural number of ten, it indicates the age, and also refers to the approximate age of a person.

i. Used with plural nouns to refer to the entire group

j. Used before nouns for body parts or clothing of people mentioned earlier.