RULES TO THE DEFINITE ARTICLE "THE"
with names of geographic regions
With the name of universities, colleges, and schools when the name begins with the words university, college or school
When something is common knowledge
10.the expressions THE NUMBER OF refers to the group and takes a singular verb
when the name of a country or state includes the word OF, the TYPE OF GOVERNMENT, or A PLURAL FORM , or have an ADJECTIVE IN THE NAME
With proper names of bridges, canals, gulfs, deserts, jungles, forests, oceans, rivers, seas, plural lakes, plural islands or group of islands with a plural name, plural mountain ranges
Before a body part in a prepositional phrase that belongs to the object in the sentence, or to subject of a passive sentence
When there is only ONE of something
Before adjectives used as nouns or nationalities
Before a singular noun that refers to species or group or specific noun.
When it is clear in the situation which thing or person s referred to, this is, when both the speaker and the listener have a specific thing or person in mind
Before a noun that has already been mentioned, this is, the second time the speaker mentions a noun
Before any noun, singular, plural, count or noncount.
With the name of wars
With superlative of adjectives.
With words like office, movies, theater.
With the name of historical documents
RULES TO USE INDEFINITE ARTICLE "A"
Before a consonant sound.
Before singular count nouns when the noun is mentioned the first time, or to introduce a subject.
"A" is not used before a noncount noun.
When the singular form is used to make a general statement about all people or things of that type.
Before singular countable nouns that mean "one"
With names of professions
With expressions of price, speed, and ration or with certain numerical expressions.
With the expression A NUMBER OF means several or MANY and takes plural verbs
When indefinite nouns are mentioned (they are actual things, not symbols, but they are not specifically identified)
RULES FOR INDEFINITE ARTICLE "AN"
When indefinite nouns are mentioned (they are not actual things, not symbols, but they are not specifically identified)
Use "an" before a slient or unsounded "h."
Before a vowel or a vowel sound.