A verbal phrase is the union of two or more verbs that function together as a single verbal nucleus. The first verb carries tense, mood, person, and number, and the second verb usually appears in a non-inflected form, such as an infinitive, participle, or gerund. The verbal phrase can be interrupted by unstressed pronouns, short adverbs, or clitics without losing its unity. In Portuguese, verbal phrases are used to form compound tenses, aspectual periphrases, and voice constructions.

The second verb in a verbal phrase normally appears in the infinitive, the gerund, or the participle. Each choice is linked to the meaning of the phrase and to the structure required by the first verb. Compound tenses use the participle, continuity periphrases use the gerund, and periphrases of intention or futurity typically use the infinitive. The correct choice preserves agreement and avoids ambiguity in the sentence.

Portuguese compound tenses are formed by a conjugated auxiliary verb, usually 'ter' or 'haver', plus the participle of the main verb. This structure expresses anteriority relative to another time, as in the present perfect compound and future perfect compound. The participle agrees in gender and number only when there is analytic passive voice with 'ser' or 'estar', not with 'ter' and 'haver'. In formal registers, 'haver' is more frequent in writing, and 'ter' is dominant in speech.

Aspect periphrases are verbal phrases that express continuation, initiation, conclusion, or repetition of an action. They combine an auxiliary verb with semantic meaning and a second verb in the infinitive or gerund. 'Estar + gerund' indicates an action in progress, 'vir a + infinitive' indicates result or eventuality, 'acabar de + infinitive' indicates a recently completed action, and 'começar a + infinitive' indicates the start of an action. The aspectual meaning depends on the chosen auxiliary and does not change the tense without altering the inflection of the first verb.

Some verbs appear very frequently as auxiliaries in Portuguese verbal phrases. 'Ter' and 'haver' form compound tenses with a participle, 'ser' and 'estar' form the analytic passive voice with a participle and state, and 'ir' builds a near-future periphrase with the infinitive. Other auxiliaries, such as 'dever' and 'poder', form periphrases of obligation and possibility with the infinitive. The choice of the auxiliary determines the main meaning of the phrase.

In verbal phrases, the position of unstressed pronouns depends on the choice among proclisis, mesóclisis, and enclisis, according to the syntactic context. When the auxiliary is conjugated and the main verb is in non-personal form, the pronoun may appear before the auxiliary, after the auxiliary, or attached to the main verb. In contemporary Brazilian Portuguese, it is common to place the pronoun between the two verbs or before the entire phrase. The choice may vary by register and stylistic preference.

The use of auxiliaries in verbal phrases varies by region and by level of formality. 'Ter' is dominant in speech and informal registers for compound tenses, while 'haver' is preferred in formal writing. In some varieties, 'ir + infinitive' substitutes the simple future in everyday contexts. The passive with 'ser' remains more formal than equivalent structures with 'ficar' in many regions.

Verbal phrases in Portuguese join a conjugated auxiliary to a non-personal verb to express tense, aspect, voice, or mood. Compound tenses use the participle with 'ter' or 'haver', and aspect periphrases use the infinitive or gerund with auxiliaries such as 'estar', 'ir', and 'acabar de'. The placement of pronouns is flexible within syntactic rules, and the choice of auxiliaries may vary by region and register. Mastering these structures allows you to construct precise and natural sentences in the language.