18.1.5 the infinitive to shorten subordinate clauses
The construciton ao + infinitivo describes the punctual coincidence of two actions / events.
Ao chegar em casa, notei que a porta tinha sido arrombada.*
When I got home, I saw that the door was broken.
* Portugal: chegar a casa, Brasil: chegar em casa
In this case the construction is identical in meaning with a construction with the gerund.
Chegando a casa, notei que a porta tinha sido arrombada.
When I got home, I saw that the door was broken.
However that exception doesn't change anything to the fact that these two constructions are completely different. Only in the case that the context allows to understand the meaning, the two constructions can have the same meaning. In this example for instance the gerundio can't be substituted by a construction with the infinitive.
Bebendo um copo de vinho falaram do belo e do divino.
Drinking a glass of whine they talked the beauty and the divine.
In this case one action, drinking vine, lasts as long as the the other one, talking about the beauty and the divine are two parallel actions and can't be described with the infinitive.
The infinitive is a verbal noun in Portuguese, in opposite to the gerundio, that corresponds to the present participle, and as a noun it is introduced by a preposition and therefore it is possible to describe the relationship between the action / event of the infnitive and the action event of the finite verb. That means that more subordinate clauses can be substituted with the infinitive than with the gerundio. Furthermore in Portuguese exists the infinitivo pessoal, which is a verbal noun as well, but since it is, in opposite to what the names suggests, a finite form, it can be used as well in cases where the subject of the action described by the infinitive pessoal differs from the subject of the verb described by the finite verb. For the details about the infinitivo pessoal see chapter 16. It is useful to see that a preposistion can only be followed by something that can have the syntactical function of a noun. In other words a noun, a pronoun or an infinitive.
final clause (Describes the goal of an action.)
Fiz
um
empréstimo
para
viajar.
Made
a
loan
for
travel
I took a loan to travel.
concessive clause (One action could be a hindrance for another action, but didn't prevent this action from happening.)
Apesar de
estar
triste
ele
continua
sorridente.
Despite
being
sad
he
continues
to laugh.
Although he was said, he didn't stop laughing.
conditional clause (One action / event will only happen, if a certain condition is given.)
Não
poderá
voltar
ao
trabalho
sem
me
avisar
com
antecedência.
Not
you will can
return
to
work
without
me
informed
with
advance.
You can't return to work without having informed me first.
(This is not a typicial conditional clause, although very similar: If you had not informed me first, you can't return to work. A typical conditional clause can't be formed with the infinitive, because to the conjunction se there is no equivalent preposition.)
temporal clause (Describes the chronology of two actions / events. Anteriority, simultanity, posteriority.)
Alegraram-se
ao receber
as
medalhas.
Were glad
at receive
the
medals.
They were glad when they got the medals.
consecutive clause (One action is the result of an another action. The opposite of a causal close. He didn't have any money, therefore he couldn't pay the bill. <=> Because he didn't have any money, he couldn't pay the bill.)
Ele
se
distraiu
tanto
a ponto
de esquecer
a
discussão.
He
himself
distracted
so much
to point
of forget
the
discussion.
He was so absent-minded that he forgot completely the discussion.
causal clause (Describes the cause of something. The opposite of a consecutive clause. He felt asleep, therefore he didn't realized it. <=> Because he didn't realized it, he felt asleep.*)
Por
ter chegado
tarde
não
havia
ninguém
na
recepção.
Because
having come
late
not
has
nobody
at the
reception.
Since he came to late, there was nobody at the reception.**
adversative clause (I opposite to the concessive clause the adversative clause describes an action that not only in theory could prevent another action from happening, but really did it.)
Em vez de
fazer
isso,
leia
nossas
dicas!
Instead
to make
that
read
our
tipps!
Instead of doing that read our tips.
* From a formal point of view a causal clause can always be converted into a consecutive clause. Whether the result makes sense or not, is another story.
** Since the one who came too late is not the one who wasn't at the reception, it is an infinitivo pessoal. In this case however, ter chegado = infinitivo pessoal composto, there is no big difference to an normal infinitivo, because in the 1st and 3rd person singular there is no personal ending, therefore no difference between the infinitivo and the infinitivo pessoal. In the case that it would be for instance 1st person plural, we would have a difference.
Por termos chegado tarde não havia ninguém na recepção.<=> Because we arrived late, there was nobody at the reception.
