2. When to use A and An
Only with singular nouns
When we are talking about a thing or a gender
Example I need a new laptop. Hand me a pencil , please.
With professions
Example: He is a postman.
To show a person/thing is one of the group.
Example: She is a student at our school.
With a singular noun to say something about all things of that kind.
Example: A cat likes drinking milk.