1. Use an before words that begins with vowel sound.
1.1. Examples:
1.1.1. An egg
1.2. An hour
2. Articles: According to the Oxford Dictionaries it is a determiner that introduces a noun phrase. a|an are considered indefinite articles and they are used to introduce new concepts into a discourse.
3. An + vowel (a,o,i,u,e) examples: He is an English boy,
4. Use "an" with words that start with a vowel sound
4.1. Examples:
4.2. An earth
4.3. An apple
5. Remember the use of articles a or an: We use a or an before countable nouns in the singular
6. Use "a", "an" Only with singular nouns.
7. A/AN
8. Use "a", "and" only with singular nouns.
8.1. A book
8.2. It's a computer
9. a: A + Consonant. Examples It is a pig, a brush, a car, watch
10. Remember that A(AN) means "one" or "a single". You cannot use A(AN) with plural nouns. Examples: I saw a dogs in Los Angeles National Park. Not Correct I saw a dos in Los Angeles National Park. Correct
