We know that in our Portuguese language there are ten classes of words. Of these, six are variable, as they can be inflected in gender, number, degree, person and time, they are: article, adjective, pronoun, numeral, noun and verb. Our object of study, the adverb, is among the four grammatical classes whose words are called invariables: adverb, conjunction, interjection and preposition.
The invariable words are those that do not undergo changes, thus, the adverb does not admit change in its form, and its main function is modify the verb, playing the role of adverbial adjunct in the sentence. It can also refer to another adverb to intensify it, an adjective, or an entire statement. The adverb denotes a circumstance and, depending on the situation, can be classified as an adverb of affirmation, doubt, intensity, place, mode, negation, time, etc. Let's look at some examples:
Certainly he will study for the exam.
↓
affirmation adverb
Perhapswe will travel to the beach for the July vacation.
↓
doubt adverb
The students stayed quite concerned with the outcome of the Mathematics assessment. ↓
intensity adverb
The parents were watching the child farwhile he played.
↓
adverb of place
the employee walked quickly not to be late.
↓
mode adverb
"The best definition of love no worth a kiss." (Machado de Assis)
↓
adverb of negation
“Ever/ I watched you ever/Like a cat at the owner's feet/Even in a dream I was attentive/To be able to remember you ever (...)”.
↓
adverb of time
As we have seen, adverbs are classified according to their meaning in the sentence. As for intensity adverbs, there is a particularity in relation to them, as they can modify not only the verbs, but they can also intensify the meaning of other adverbs. Watch:
Carolina was a woman extremelypretty.
↓ ↓
adjective adverb
of intensity
the friends arrived earlytoo much for the theatrical spectacle.
↓ ↓
adverb adverb
intensity time
Often the use of some invariant words can generate doubts, and these doubts are usually related to the adverb and adjective. To eliminate this type of questioning once and for all, it is important to emphasize that the adjectives are related to a noun and may vary, while the adverbs relate to verbs and do not allow variation in form.
by Laura Castro
Graduated in Letters
Source: Brazil School - https://brasilescola.uol.com.br/o-que-e/portugues/o-que-e-adverbio.htm