Written by tutor Vicki N.
The first step in choosing the proper article (a, an, the) is to determine if the noun is “countable” or “uncountable”. For example, the noun person is a “countable” noun because one or more persons can exist. I can write one person or a plural form of the noun, five persons. One way to decide is to use a dictionary which differentiates between some “countable” and “uncountable” nouns. The Cambridge Dictionaries is an online dictionary source (http://dictionary.cambridge.org). Using the American English version, a search for the noun will provide the noun and its definition along with a symbol [C] for “countable” or [U] for “uncountable”.
When to use: A/An
Use a or an when it is not necessary to know which noun is being referred to in the sentence. A or an are usually used when one refers to “countable”, singular and non-specific nouns (such as, dog, cat, boy, girl, etc.).
A is used before nouns beginning with a consonant sound.
For instance: a school, a teacher, a portable item, a playground
An is used before nouns beginning with a vowel sound.
For instance: an apple, an orange, an olive, an egg
Watch for nouns beginning with vowels that sound like a long ‘u’, such as “university”. Use “a” before these noun exceptions.
For instance: a university, a union, a eulogy
Watch for nouns or adjectives beginning with consonants that sound like a vowel, such as “hour”. Use an prior to these noun/adjective exceptions.
For instance: an hour, an honorable mention
The party is starting in an hour. We should be ready to go in 30 minutes.
The noun “hour” is countable and singular, yet is the exception as noted above. In the second sentence, the noun “minutes” is also countable, but plural. Note: No article is used when the noun is plural.
When to use: The
The cow ran from the horse. (Both nouns, cow and horse, are “countable” and specific nouns.)
Use “the” when referring to singular and plural nouns that are specific. “The cow” is a specific cow that is being referred to, not just any cow.
Jack’s luck was not good. (Luck is an “uncountable” noun; therefore, no article is used).