Indefinite Article ( a / an )

1. Use "a" if the word starts with consonant.

1.1. Example

1.1.1. a girl

1.1.2. a cat

1.1.3. a bird

2. Don´t use a/an to identify uncontable nouns. For example: Sugar, Milk, Salt, Wine, etc.

3. Use "an" if the word starts with a vowel.

3.1. Example

3.1.1. an apple

3.1.2. an umbrella

3.1.3. an eraser