A relative adverb refers to or stands for an adverbial and something that stands for an adverbial is an adverbial itself. That is always like that. A pronoun for instance, stands for a noun and is therefore a noun as well. Sometimes it can be difficult to distinguish between the relative adverb quando / when and the temporal conjunction quando / when. In the following sentence for instance quando / when is a temporal conjunction. Quando / when doesn't refer to adverbial of time, because there is none.
Eu não sei
quando
vem.
I don't know
when
he comes.
The easiest way to distinguish between a temporal clause and a relative clause is to delete the relative clause. If the result is a grammatically correct sentence, it is a relative clause, although the meaning may be altered completely. In a sentence like "All times once passed are good" we can leave out, see the following table, "once passed". The remaining sentence "All times are good" is grammatically correct and nobody has the impression that something is missing. If we leave out the temporal clause in "I don't know when he comes" we get "I don't know" and this sentence is incomplete, because it is unclear what he doesn't now.
Todos
os
tempos,
quando
passados,
são bons.
All
the
times
once
passed
are good.
All times once passed are good.
Todas
as
semanas,
quando
sua
saúde
permite,
ele
nos
acompanha.
All
the
weeks
when
his
health
allows
he
us
accompanies.
The weeks his health allows it, he accompanies us.
Já
durante
o
dia,
quando
o
corpo
gasta
mais
energia,
é
importante
que
as
refeições
sejam
compatíveis
com
este
gasto.
Already
during
the
day
when
the
body
consumes
more
energy
is
important
that
the
meals
are
compatible
with
this
consumption.
Already during the day when the body consumes more energy it is important that the meals complies the consumption.
Um dia,
quando
olhares* para trás, verás que os dias mais belos foram aqueles em que lutaste.
On day
when
you look back you will see that the best days were the days you stand up for something.
the sun shines, the secretion of melatonin is reduced.
14 pessoas foram mortas este domingo
quando
um carro carregado de explosivos explodiu num cruzamento.
14 persons died this sunday
when
loaded with explosives exploded on a crossroad.
The relative adverb should not be confused with the temporal conjunction. (Actually from a practical point of view it is completely irrelevant to see the difference, although perhaps in some circumstances it can be useful to be able to distinguish between the relative adverb and the conjunction.)
Quando can mean as well while.
Perco a noção do tempo
quando
estou escrevendo.
I lose any sense of time
while / when
I am writing.
The adverb quando can introduce a restrictive relative clause, a nonrestrictive relative clause.
non restrictive relative clause
Sábado,
quando
fomos
ao
litoral,
fez
sol.
Saturday,
when
were
at
cost
made
sun.
Saturday, when we made a trip to the coast, the sun was shining.
restrictive relative clause
Hoje
foi
o
dia
em que
o
Reino Unido
decidiu
divorciar-se
do
projeto
europeu.
Today
was
the
day
in which
the
United Kingdom
decided
to divorce
of
project
European.
Today was the day the United Kingdom decided to dissociate itself from the European project.
Tudo
aqui
lembra
o
tempo
quando
eu
vivia
no
interior.
Everything
here
remembers
the
time
when
I
lived
in the
interior
Everything here recalls to my mind the days when I lived inside the country.
O
dia
quando
a
Suécia
mudou
a
mão
de
todas
as
suas
ruas.
The
day
when
the
Sweden
changed
the
direction of travel
of
all
the
its
streets.
The day Sweden changed the direction of travel of all its streets.
