a

/ˈeɪ/

/ˈeɪ/, /ə/

used when we want to talk about a person or thing for the first time or when other people may not know who or what they are

1.1

used before a noun when we are not talking about a specific person or thing

Esempio

1. The wheel of the bicycle had a hub at its center.

2. Opportunity makes a thief.

3. A pilot must have good vision and quick reflexes.

4. My grandmother made a dress for me.