Articles and nouns both have plural forms. See the table below for the plural forms of the articles.
If a noun ends in a vowel we add -s to make it plural.
|el libro (the book)||los libros (the books)|
|un libro (a book)||unos libros (some books)|
If a noun ends in a consonant we add -es to make it plural.
|la ciudad (the city)||las ciudades (the cities)|
|una ciudad (a city)||unas ciudades (some cities)|
There are actually some exceptions to the -es rule, but you will learn them in a later lesson.