A, an and the: small words, big difference
Learn when you are introducing something new and when you mean something already known.
2 min read · Updated 9/8/2026
The key idea
A singular countable noun usually needs a determiner: a book, the book, my book.
A/an can point to one member of a group, or to something you are introducing for the first time. The is used when it is clear to both the speaker and the listener which thing is meant.
The choice of a/an depends on the sound, not the letter: a university, an hour. In a general sense, a plural noun can have no article: Books are useful.
See an example
I bought a book yesterday. The book is about travel.
First we introduce the book, then we talk about that same book.
She wants to become an engineer.
Here an comes before a singular noun that names a profession. Engineer begins with a vowel sound.
Now you try
Complete the gaps with a, an, the or no article.
- He studies at ___ university in Baku.
- I found a café. ___ café closes at six.
- ___ students need time to rest. (students in general)
A personal draft. It is not saved when you leave or automatically graded.
Reveal the answer and explanation
Answer and explanation
- a — university begins with the consonant sound /j/.
- The — it is the café we introduced in the previous sentence.
- No article — the sentence is about students in general, not about a particular group.
A question to check yourself: “Is this just any example, or something I have already identified?”
Why are advice and information never plural?
Official sources for this topic
British Council · Grammar