Ora caminhamos de dia, ora usamos a lanterna frontal à noite.

Here, ora ... ora ... is a paired expression that shows alternation: one thing happens at one time, and another happens at another time.

In English, it often corresponds to:

• sometimes ... sometimes ...
• now ... now ...
• at one time ... at another

So in this sentence, ora does not mean literal now. It is a linking word that sets up two alternating situations.

It can sound a little more literary or carefully written than very everyday alternatives, but it is perfectly natural.

Because this is a correlative structure: the pattern is ora X, ora Y.

Portuguese repeats ora before each contrasting or alternating part:

• Ora caminhamos de dia, ora usamos a lanterna frontal à noite.

That repetition is what creates the meaning of one time this, another time that.

Portuguese often leaves out subject pronouns when the verb ending already makes the subject clear.

Both caminhamos and usamos end in -amos, which tells you the subject is we.

So:

• (Nós) caminhamos
• (Nós) usamos

Both are correct, but leaving out nós is very common and natural.

Yes, here they are understood as present tense, describing something habitual or repeated.

So the idea is not a single event, but a pattern:

• sometimes we walk during the day
• sometimes we use the headlamp at night

A useful thing to know is that for -ar verbs, the we form in the present and the simple past can look identical:

• caminhamos = we walk / we walked
• usamos = we use / we used

The context tells you which meaning is intended. Here, the expressions de dia and à noite, together with ora ... ora ..., strongly suggest a habitual present meaning.

De dia is a very common expression meaning:

• during the day
• in the daytime
• by day

It is an idiomatic time expression. Learners often want to translate word by word, but it is best to learn de dia as a set phrase.

Compare:

• de dia = in the daytime
• à noite = at night

They work as a natural pair.

Because à is the contraction of:

• the preposition a
• plus the feminine singular article a

So:

• a + a = à

In time expressions, à noite is the normal fixed form for at night.

The grave accent is important because it shows this contraction.

By contrast, de dia uses the preposition de, so there is no similar contraction there.

Because de dia is simply the idiomatic expression Portuguese uses.

Languages often choose different prepositions in fixed time expressions, and these do not always match English logic exactly. So the best approach is to learn them as chunks:

• de dia
• à noite
• de manhã
• à tarde / de tarde depending on usage and region/context

So even if another preposition might seem logical to an English speaker, de dia is the natural form here.

Lanterna frontal means a headlamp or head torch.

In European Portuguese:

• lanterna usually means a portable light such as a flashlight/torch
• frontal means it is worn at the front, on the head/forehead

So lanterna frontal is the standard way to describe the light you wear on your head while walking, hiking, running, and so on.

Because in Portuguese, adjectives often come after the noun.

So:

• lanterna frontal = literally lantern frontal

This is especially common with descriptive or classifying adjectives. Here, frontal is classifying the kind of lantern/light it is.

That word order is the normal one.

Portuguese often uses the definite article more freely than English does.

So usamos a lanterna frontal can sound very natural if the speaker means:

• the headlamp we use in that situation
• the usual/known headlamp for this activity

Without the article, usamos lanterna frontal is not impossible, but it can sound a bit more generic or less anchored to a specific item.

In many cases, Portuguese prefers the article where English would simply say we use a headlamp or we use headlamps.

The comma separates the two parts of the correlative structure:

• Ora caminhamos de dia,
• ora usamos a lanterna frontal à noite.

With paired expressions like ora ... ora ..., the comma helps show the contrast or alternation clearly. It is the normal punctuation here.

Yes. Some more everyday alternatives are:

• Às vezes caminhamos de dia, outras vezes usamos a lanterna frontal à noite.
• Por vezes caminhamos de dia, por vezes usamos a lanterna frontal à noite.

These are often more straightforward for learners.

Compared with those:

• ora ... ora ... is a bit more compact
• it can sound slightly more formal, literary, or stylistically polished

Yes. Portuguese allows some flexibility in word order.

For example:

• Ora de dia caminhamos, ora à noite usamos a lanterna frontal.

That version is also possible, but it changes the rhythm and emphasis a little. It puts stronger focus on the time expressions.

The original sentence is very natural and balanced:

• Ora caminhamos de dia, ora usamos a lanterna frontal à noite.