ARTICLES

use a/an when it's the first time something is mentioned. ( I saw a movie)

with job (Marlin is a teacher)

the indefinite article a is used before a consonant sound. (a pilot, a teacher, a union, a university)

the indefinite article an is used before a vowel sound (a athlete, an elephant)

when we mention something for the first time we use a or an the next time we repeat that object we use the definite article the. ( i bought a car. the car is red)

when the subject is unique/there's only one.(the president will be speaking on tv tonight)

with superlatives (this is the highest building in Banjarbaru)

with countries that have plural names, kingdom or republics. ( she really loves the united states)

with river, seas, ocean, deserts (the pasicif ocean)

to describe where in a country or city (they live the south of the city)