a, an

A and an mean "one", but not a particular one. They go before one thing you can count: a book, an apple. They never go before a plural (books) or before words you can't count, like water or music.

A or an: the sound decides

Use an before a vowel sound and a before a consonant sound. Most of the time this follows the first letter: a cat, an egg. But the sound is what counts, not the letter.

• u that sounds like "yoo" takes a: a university, a uniform
• o that sounds like "w" takes a: a one-way ticket
• a silent h takes an: an hour, an honest man

When there's an adjective, the adjective's first sound decides.

Jobs

Say what someone's job is with a or an.

A first, then the

Use a when you mention something for the first time. When you talk about it again, the listener knows which one, so use the.

Common mistakes

• × She is nurse. → She is a nurse.
• × an university → a university
• × a hour → an hour
• × a water, × a music → some water, music
• × I have a books. → I have books. or I have two books.