In Spanish, these words can also exist in the plural form; unos and unas are known as the plural indefinite articles. Although they don't have an exact English equivalent, they are usually translated as "some" or "a few"; if one is used before a number, it usually means "about" or "approximately." Like adjectives, the article must agree with the noun in number and gender. See examples of the plural indefinite article in these sample sentences:
- Compré unas manzanas. I bought a few apples.
- Unos alumnos salieron. Some students left.
- Tengo unos casetes nuevos. I have some new cassettes.
- La película duró unos noventa minutos. The film lasted about 90 minutes.
- Tomamos unos refrescos. We had some soft drinks.
- Necesité unas horas para leer el libro. I needed a few hours to read the book.
As is the case with singular indefinite articles, the plural article is needed before each of the items in a series: Compré unas manzanas y unas peras. I bought some apples and pears.
If unos or unas is used before an item that exists in the plural to refer to a single object (as "pants" or "glasses" in English), the article can mean "one" or "one pair": Necesito unas gafas de buceo. I need a pair of diving goggles.