Articles: a/an

A noun like house, engineer, girl, name refers to a whole class of people or things.
We use a/an with a noun to talk about just one member of that class. (A/an means 'one'.)

• She lives in a nice big house.


• My father is an engineer. (NOT My father is engineer.)


• A girl phoned this morning.


• Tanaka is a Japanese name.

We use a/an when we define or describe people or things (when we say what class or kind they belong to).

• He's a doctor.


• She s a beautiful woman.


• 'What's that?' 'It's a calculator.'

We do not use a/an with a plural or uncountable noun, because a/an means 'one'.

• My parents are doctors (NOT . . . a doctors.)


• Would you like some salt?(NOT . . . a salt.)

We do not use a/an with an adjective alone (without a noun). Compare:

• She's a very good engineer.


• She s very good. (NOT She's a very good.)

We do not use a/an together with another determiner (for example my, your).

• He's a friend of mine (NOT He's a my friend)
  

Note that we write another in one word.

• Would you like another drink? (NOT . . . an other drink?)