In short

Many Portuguese verbs and adjectives do not connect to their complement directly - they demand a specific little preposition first, and that preposition is fixed. You do not gostar a thing, you gostar de it; you do not pensar a person, you pensar em them. This is called regência (government): the verb or adjective “governs” which preposition must follow. The catch for an English speaker is that the Portuguese choice almost never matches the English one - “depend on” is depender de, “wait for” is esperar por, “dream of” is sonhar com. There is no rule that predicts the right preposition, so the working method is to learn each verb together with its preposition as a single chunk - precisar de, assistir a, pensar em - exactly the way you memorised a word.

The rule

The preposition belongs to the verb, not to the meaning

Portuguese groups these verbs into loose families by the preposition they take. The families are not logical - they are just what you must memorise - but sorting them this way makes them far easier to store.

• de: gostar de, precisar de, lembrar-se de, esquecer-se de, depender de, desistir de, duvidar de, aproximar-se de.
• a: assistir a (to watch / attend), obedecer a, responder a, pertencer a, dedicar-se a, habituar-se a, referir-se a.
• em: pensar em, acreditar em, insistir em, reparar em (to notice), participar em, consistir em.
• com: sonhar com, preocupar-se com, importar-se com, casar com, parecer-se com, contar com, concordar com.
• por: esperar por (to wait for), apaixonar-se por, interessar-se por, optar por, responsabilizar-se por.
• para: olhar para (to look at), contribuir para.

Adjectives govern prepositions too

The same machinery runs on adjectives: cheio de (full of), cansado de (tired of), contente com (happy with), interessado em (interested in), apaixonado por (in love with). Again the preposition is fixed and does not track English.

• de: cheio de, cansado de, capaz de, orgulhoso de, diferente de, fácil de / difícil de (+ infinitive).
• com: contente com, satisfeito com, zangado com, parecido com, compatível com.
• em: interessado em, rico em.
• a: semelhante a, igual a, fiel a, superior a, sensível a.
• por: apaixonado por, responsável por, conhecido por.
• para: útil para, pronto para, bom para.

The preposition fuses with what follows

The governed preposition still obeys the contraction rules you already know. When an article or a demonstrative comes next, the two merge: gostar de + o café -> gostar do café, assistir a + o jogo -> assistir ao jogo, pensar em + o futuro -> pensar no futuro, apaixonar-se por + a Ana -> apaixonar-se pela Ana. It also happens before demonstratives: de + isso -> disso, em + isso -> nisso, a + aquilo -> àquilo. The preposition never disappears - it is just hiding inside do, ao, no, pela, disso.

It survives before an infinitive

The verb or adjective keeps its preposition even when the complement is a whole action expressed by an infinitive: Gosto de viajar, Preciso de descansar, Estou cansado de esperar, Estou pronto para começar, Insisto em pagar. So “I need to talk” is Preciso de falar - the de is not optional filler, it is the government of precisar.

Clitics stay enclitic

Several of these verbs are reflexive (lembrar-se, apaixonar-se, preocupar-se, dedicar-se), so the pronoun follows EP’s default enclisis: Lembro-me de ti, Apaixonei-me por ela, Preocupo-me com isso. After a negation the pronoun moves in front, as usual: Não me lembro de nada.

Forms & patterns

Common verbs, sorted by the preposition they govern:

Common adjectives, same idea:

Examples

Common mistakes

• Gosto música -> Gosto de música - gostar always governs de; you can never drop it, and de + a música would contract to da música.
• Depende em ti -> Depende de ti - depender takes de, not the English “on/em”.
• Penso sobre ti / penso de ti -> Penso em ti - “think about” is pensar em; sobre and de are both wrong here.
• Ela casou o João -> Ela casou com o João - casar governs com, even though English “marry someone” has no preposition.
• Espero para o autocarro -> Espero pelo autocarro (or Espero o autocarro) - “wait for” is esperar por, which fuses to pelo; para points at a goal, not the thing awaited.
• Gosto de o café -> Gosto do café - the governed preposition must fuse with the article: de + o = do, a + o = ao, em + o = no, por + o = pelo.
• Assisti o filme -> Assisti ao filme - in the “watch/attend” sense, assistir takes a (ao). In Brazil this preposition is routinely dropped in speech (assisti o filme), but in European Portuguese keep the a.

Tips

• No rule predicts the preposition, so store the pair as one word: not “gostar + something”, but gostar de, precisar de, pensar em, sonhar com. Learn the chunk, and the sentence builds itself.
• Keep a short list of the English mismatches taped to your memory: think about = pensar em, depend on = depender de, wait for = esperar por, dream of = sonhar com, look at = olhar para. These are where you will actually slip.
• The preposition never vanishes - it contracts. When you hear do, ao, no, pela, disso, nisso, àquilo, remember there is a governed de / a / em / por inside it.
• The government holds before an infinitive too: preciso de descansar, cansado de esperar, pronto para sair. Do not strip the preposition just because an action follows.
• Reflexive members keep EP enclisis - lembro-me de, apaixonei-me por, dedico-me a - and switch to proclisis only after a negation or a trigger word: não me lembro de, quando me apaixonei por.