2. According to the orford dictionary it is a determining that introduces it is a determining that introduces a noun phrase. a/ one indefinite articles are considered and use to introduce new concepts in a speech
3. https://www.youtube.com/watch?v=sL6jqw_Adsw
4. RULES
4.1. 1. use "an" with words beginning with a vowel sound. 2. Use "a", and only singular nouns.