INDEFINITE ARTICLES

1. EXAMPLE

1.1. A Dog

1.2. A Book

1.3. A ball

2. AN

2.1. Use “an” with words that start with a vowel sound

2.2. Vídeo

3. A

3.1. Use “a”, “and” only with singular nouns

3.1.1. 1st Sitting

3.1.2. 2nd Sitting

3.1.3. 3rd Sitting

3.2. Video

4. 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.

5. EXAMPLE

5.1. An Ant

5.2. An Ice Cream

5.3. An Hour