The cardinal numbers are very similar in Spanish and Portuguese, but there are differences of usage in numbers one and two. Spanish has different words for the masculine singular indefinite article ('a, an') and the numeral 'one', thus un captulo 'a chapter', but captulo uno 'chapter one'. In Portuguese, both words are the same: um captulo and captulo um. Spanish uno can also be used as a pronoun, like the English generic "one", to represent an indeterminate subject, but this is not possible with Portuguese um; the reflexive pronoun se must be used instead. Se may be used in Spanish to form passive and impersonal constructions, as well.[8]