Use a or an with a singular countable noun when the listener doesn't know which one you mean, or it doesn't matter: I talked to a manager. Also to say what someone or something is: She's an engineer. Use an before a vowel sound: an hour, a university.
I talked to a manager yesterday.
One of several, and the listener can't tell which one. It's new information, or it simply doesn't matter.
| Singular countable | Yes: a book, an idea |
|---|---|
| Plural | No: I bought books. (not a books) |
| Uncountable | No: some advice, a piece of advice (not an advice) |
A or an depends on the first sound, not the first letter: a uniform (it starts with a 'you' sound), a one-way ticket ('wun'), an hour (silent h), an MBA ('em').
I met a woman from Brazil at the conference.
The first time you mention something, the listener doesn't know it yet.
Can I borrow a pen?
Any pen will do. You're not thinking of a particular one.
She's an architect. It's a great idea.
Saying what someone or something is puts it in a group. English needs a or an here.
Twice a week. €5 a kilo. Half an hour.
With numbers, prices and frequency, a means 'one' or 'each'.
Common expressions worth learning as they are.
My brother is _____ doctor.
A, the or nothing: every rule on one page.
Paste an email or an essay. Clarigram marks the mistakes you actually make, shows the rule behind each one as a picture, and builds your practice from them.
It's about sound, not spelling. In hour the h is silent, so the word starts with a vowel sound. In house you pronounce the h.
Modern English uses a historic, because the h is pronounced. An historic is an older style you may still see in British writing.
Not directly. Use some, or a unit: a piece of advice, a glass of water. Some nouns are both: coffee is uncountable as a drink, but a coffee means a cup of coffee.