The Impersonal Se (Formal Usage)

• With Intransitive Verbs: These verbs do not require an object. The se makes the statement general.
• Vive-se bem nesta cidade. (One lives well in this city / People live well here.)
• Morre-se uma só vez. (One dies only once.)

• With Transitive Verbs Requiring a Preposition (Transitivo Indireto): When the verb is followed by de, a, em, com, etc., the se signals an indeterminate agent.
• Precisa-se de voluntários para o evento. (Volunteers are needed for the event / One needs volunteers.)
• Gosta-se muito de festas populares em Portugal. (Popular festivals are much liked in Portugal / People really like popular festivals.)
• Acredita-se em mudanças significativas. (Significant changes are believed in / One believes in significant changes.)

• With Verbs of Emotion/Perception: Often used to express general feelings or observations.
• Sente-se um clima de otimismo. (A climate of optimism is felt / One feels a climate of optimism.) – Note: clima is the object of sentir, but the impersonal nature takes precedence, especially if the verb is used more abstractly. However, Sente-se o clima (The climate is felt) could be passive se.

• Verb agrees with the nominal subject:
• Vende-se apartamento com vista para o mar. (An apartment with a sea view is sold.) – apartamento is singular, so vende-se is singular.
• Vendem-se apartamentos com vista para o mar. (Apartments with a sea view are sold.) – apartamentos is plural, so vendem-se is plural.

• Formation: Active sentence: Eles venderam a casa. (They sold the house.) → Passive se: Vendeu-se a casa. (The house was sold.)
• Active sentence: Eles construíram vários edifícios. (They built several buildings.) → Passive se: Construíram-se vários edifícios. (Several buildings were built.)

• Negative Adverbs: não, nunca, jamais, nem, ninguém, nada.
• Não se deve procrastinar. (One should not procrastinate.)
• Nunca se viu tamanha dedicação. (Such dedication was never seen.)

• Indefinite Pronouns/Adverbs: tudo, alguém, algo, onde, sempre, já, ainda, talvez, aqui, lá, muito.
• Tudo se resolveu pacificamente. (Everything was resolved peacefully.)
• Aqui se fala português. (Portuguese is spoken here.)

• Relative Pronouns: que, quem, cujo, onde.
• A questão que se debate é complexa. (The issue that is debated is complex.)
• Foi um período em que se cometiam muitos erros. (It was a period when many mistakes were made.)

• Subordinating Conjunctions: quando, enquanto, se (conditional), embora, conforme, porque.
• Quando se quer, tudo se alcança. (When one wants, everything is achieved.)
• Embora se saiba a verdade, poucos agem. (Although the truth is known, few act.)

• Interrogative Pronouns/Adverbs: quem, que, quando, como.
• Quem se responsabiliza por isso? (Who takes responsibility for this?) – This is technically se as a reflexive, but the principle applies.
• Como se faz isso? (How is this done?)

• This is the default placement when no attracting word precedes the verb, most notably at the beginning of a sentence or clause.
• Fez-se o trabalho. (The work was done.)
• Espera-se que o problema seja resolvido. (It is hoped that the problem will be resolved.)

• Reserved for verbs in the future simple (-ei, -ás, -á, etc.) or conditional simple (-ia, -ias, -ia, etc.) tenses, when no word triggers proclise.
• Far-se-á o necessário. (The necessary will be done.)
• Dir-se-ia que houve um engano. (It would be said that there was a mistake.)
• While grammatically correct and sometimes found in very formal EP, mesoclise is considerably less common in modern BP, where proclise (if triggered) or enclise with a periphrastic construction (e.g., irá fazer-se or vai fazer-se) are generally preferred. However, for C1-level academic Portuguese, especially if influenced by EP norms, awareness and correct application of mesoclise are valuable.

• Impersonal Se: Vendem-se casas. (Houses are sold.)
• Analytical Passive: As casas são vendidas. (The houses are sold.)

• When to choose:
• Synthetic Passive (se): Often more concise and elegant, especially in formal writing and headlines. It emphasizes the action rather than the state resulting from the action. Generally preferred when the agent is truly unknown or irrelevant.
• Analytical Passive: Allows for the explicit mention of the agent using por or pelo/a/os/as (As casas são vendidas pelos corretores.). It can also emphasize the state of being acted upon. Offers more flexibility with verb tenses and aspects.

• Impersonal Se: Precisa-se de mais foco. (More focus is needed.)
• Impersonal Expression: É preciso ter mais foco. (It is necessary to have more focus.)
• When to choose: Both are valid. The se construction is typically more formal and succinct, often found in directives or formal observations. É preciso is also formal but can feel slightly less academic or legalistic.

• Impersonal Se: Falam-se línguas aqui. (Languages are spoken here.)
• Indefinite Pronoun: Alguém fala línguas aqui. (Someone speaks languages here.)
• Informal Indefinite Subject: A gente fala línguas aqui. (We speak languages here – informal BP.)
• When to choose: These are suitable for more informal contexts or when you want to vaguely suggest a human agent without naming them. A gente is highly informal and characteristic of spoken Brazilian Portuguese.

• Ao se analisar os dados, percebe-se... (Upon analyzing the data, one perceives...)
• Para se compreender o fenômeno, é preciso... (To understand the phenomenon, it is necessary...)
• This construction is particularly elegant for presenting conditions or purposes in an impersonal manner.

• Ele arrependeu-se dos seus erros. (He regretted his errors.) – Here, se is part of arrepender-se.
• Contrast with true impersonal: Arrepende-se dos erros. (One regrets the errors.) – This uses the same verb but the se here is impersonal, hence the singular agreement, as arrepender-se acts like an intransitive/prepositional verb.

Not exactly. In the true impersonal se (Precisa-se de voluntários), se acts as an indeterminate subject pronoun, but the verbal phrase as a whole (precisa-se) indicates that "one" or "people" are performing the action. In the passive se (Vendem-se casas), the se is a passive marker, and the noun (casas) becomes the grammatical subject with which the verb agrees. So, its role is complex; it signals impersonality or passivity rather than always being the semantic agent.

Grammatically, you could, but you would sound overly formal, even robotic. For informal communication, stick to você (you), a gente (we/people – especially in BP), or simply active voice without an explicit subject if context allows.

With compound tenses or verbal periphrases, the se can often be placed in two positions, especially in BP, though EP tends to be more prescriptive.

• Attached to the auxiliary verb: Deve-se fazer. (One should do / It should be done.)
• Attached to the main verb (infinitive/gerund): Deve fazer-se. (One should do / It should be done.)

The fundamental grammatical rules for formation and agreement are largely the same. The main difference lies in pronoun placement (próclise/ênclise). While both varieties adhere to the rules of proclise triggers (negative words, relative pronouns, etc.), BP is much more tolerant of proclise in contexts where EP would strictly require enclise (e.g., at the beginning of a sentence: BP informal Se faz, EP/BP formal Faz-se). For C1-level formal writing, irrespective of regional variety, adhering to the stricter EP placement rules (no initial se without an attracting word) is generally advisable.

No. By definition, the impersonal se obscures or generalizes the agent. If you intend to refer to a specific person or group, you must use a different construction (e.g., a named subject, a personal pronoun, or the analytical passive with an agent). The power of the impersonal se is precisely its ability to abstract away from specific agency.