✓A ✗An

Technology is a useful servant but a dangerous master.
La tecnologia è un servo utile ma un padrone pericoloso.
– Christian Lous Lange
✓ Pavia is a university town.
Pavia is *an university* town.
Pavia è una città universitaria.
Generally we use a + consonant (a dictionary, a nice day, a party), and an + vowel (a, e, i, o or u) (an aunt, an idea, an ugly dog).

There are two “exceptions” to this “rule”. The first is that we use a, not an, before words beginning with u- or eu- pronounced like the letter u (pronounced “you”). Some examples:
a unit of measurement, a UFO, a union member, a euphemism, a European capital
*an unit* of measurement, *an UFO*, *an union* member, *an euphemism*, *an European* capital
un’unità di misura, un UFO, un iscritto al sindacato, un eufemismo, una capitale europea
Note that these are not really “exceptions”, but simply a question of pronunciation. Try saying “a Euro” and “an Euro”. Which is easier? The first, of course (if you pronounce Euro correctly, that is, “you-roh”).
The second “exception” is before a “mute h”. There are only four words in the English language, all of French origin, which begin with a silent h: hour, honest, honour and heir (and their derivations, such as honourable or heiress). Examples:
✓ See you in an hour!
✗ See you in *a hour*!
Ci vediamo tra un’ora!
✓ I’d like an honest opinion.
✗ I’d like *a honest* opinion.
Vorrei un parere sincero.
✓ It would be an honour for me.
✗ It would be *a honour* for me.
Sarebbe un onore per me.
✓ The king and queen have no children, so there isn’t an heir to the throne.
✗ The king and queen have no children, so there isn’t *a heir* to the throne.
Il re e la regina non hanno figli, quindi non c’è un erede al trono.
In all other words beginning with h, the h is pronounced, and so we use a:
✓ There’s a hotel near the station.
✗ There’s *an hotel* near the station.
C’è un albergo vicino alla stazione.
✓ I had a bad dream last night – I’d watched a horror film.
✗ I had a bad dream last night – I’d watched *an horror* film.
Ho fatto un brutto sogno stanotte – avevo guardato un film d’orrore.

Now try the quiz below! There are TEN answers. The pass mark is 90% (9 out of 10). Click on the blue arrows to go to the next or previous question. You can check your answers immediately or when you’ve finished the quiz.