De vez em quando o meu olho dói quando estudo até tarde.

Sometimes my eye hurts when I study until late.

Breakdown of De vez em quando o meu olho dói quando estudo até tarde.

• meu: my
• estudar: to study
• tarde: late
• até: until
• quando: when
• o olho: the eye
• de vez em quando: from time to time
• doer: to hurt

Questions & Answers about De vez em quando o meu olho dói quando estudo até tarde.

What does de vez em quando literally mean, and is it the same as às vezes?

De vez em quando literally means something like from time to time or every now and then.
Às vezes means sometimes.

In everyday use, they overlap a lot, and both are very common in Portugal. Rough nuance:

• de vez em quando – sounds a bit like from time to time / every now and then
• às vezes – sounds a bit more like sometimes

You can usually swap them without changing the meaning much:

• De vez em quando o meu olho dói…
• Às vezes o meu olho dói…

Both are fine and natural in European Portuguese.

Can de vez em quando go in another position in the sentence?

Yes. Time expressions in Portuguese are relatively flexible. All of these are possible:

• De vez em quando o meu olho dói quando estudo até tarde.
• O meu olho, de vez em quando, dói quando estudo até tarde. (more emphatic, more written style)
• O meu olho dói, de vez em quando, quando estudo até tarde.
• O meu olho dói quando estudo até tarde, de vez em quando.

The most neutral-sounding in speech is probably the original one, with de vez em quando at the beginning or just after the subject:

• De vez em quando o meu olho dói…
• O meu olho, de vez em quando, dói…

Why is there an o before meu olho? Can I just say meu olho?

In European Portuguese, it’s very common to use the definite article with possessives:

• o meu olho – literally the my eye

Using the article often sounds more natural in Portugal, especially in subject position:

• O meu olho dói. ✅ (very natural)
• Meu olho dói. ✅ (still correct, but in Portugal it can sound a bit more marked, informal, or emphatic, depending on context)

In Brazilian Portuguese, meu olho dói (without o) is more common.
In European Portuguese, o meu olho dói is the default choice.

Is there any difference in meaning between o meu olho dói and meu olho dói?

Not really in meaning; both mean my eye hurts.

The difference is mostly in:

• regional preference
  
  • Portugal: o meu olho dói is the normal, neutral version.
  • Brazil: meu olho dói is more typical.
• style/feel in European Portuguese
  
  • With article (o meu olho): more neutral and standard.
  • Without article (meu olho): can sound a bit more informal, or used for emphasis in some contexts.

For sounding natural in Portugal, prefer o meu olho here.

Why is it dói and not something like doi or doí? How does the verb doer work?

Doer is the verb to hurt / to ache. It’s irregular.

• Infinitive: doer
• 3rd person singular present: dói
• 3rd person plural present: doem

The accent in dói shows that:

• the word is stressed on the one syllable dói
• the ó is an open o sound (like in British English lot, but shorter)
• it’s not pronounced like doi in English (not doy with an English oy diphthong)

Agreement:

• O meu olho dói. – My eye hurts. (singular subject)
• Os meus olhos doem. – My eyes hurt. (plural subject)

So dói is correct here because o meu olho is singular.

Could I say Os meus olhos doem quando estudo até tarde instead? Is that also correct?

Yes, that is perfectly correct, but it changes the meaning slightly:

• O meu olho dói… – one eye hurts
• Os meus olhos doem… – both eyes hurt / my eyes hurt

Both are grammatically fine. You just choose singular or plural depending on what you want to say.

Why doesn’t the sentence say Dói-me o olho instead of O meu olho dói? Which is more natural in Portugal?

Both are possible and correct in European Portuguese:

• O meu olho dói quando estudo até tarde.
• Dói-me o olho quando estudo até tarde.

Differences:

• Dói-me o olho is very idiomatic and common in Portugal for talking about pain. It literally means The eye hurts me, with -me = to me.
• O meu olho dói is also correct and understandable. It can feel slightly more neutral or “textbooky”.

In real-life European Portuguese, many speakers might naturally say:

• De vez em quando dói-me o olho quando estudo até tarde.

So if you want to sound very natural and European, dói-me o olho is an excellent pattern to learn:

• Dói-me a cabeça. – My head hurts.
• Dói-me o braço. – My arm hurts.

Why is it estudo instead of estou a estudar for “when I study until late”?

Portuguese uses the present simple a lot for:

• habitual actions
• general situations

Here, quando estudo até tarde means:

• when(ever) I study until late
• whenever I stay up late studying

So estudo (present simple) is perfect for a repeated, habitual action.

Estou a estudar (European Portuguese) / estou estudando (Brazilian Portuguese) expresses an action in progress right now:

• O meu olho está a doer quando estou a estudar até tarde.
  – sounds like you are describing a specific ongoing situation, not a general habit.

For the general statement in your sentence, estudo is the natural choice.

Why is eu omitted before estudo? Could I say quando eu estudo até tarde?

In Portuguese, subject pronouns (eu, tu, ele, etc.) are often dropped because the verb ending already shows the person:

• estudo → clearly 1st person singular (eu)

Both versions are correct:

• quando estudo até tarde ✅
• quando eu estudo até tarde ✅

Using eu can:

• add contrast or emphasis (when I study late, as opposed to someone else)
• sound a bit more formal or explicit in some contexts

In a neutral sentence without contrast, the pronoun is usually omitted:

• O meu olho dói quando estudo até tarde.

Why is quando used? Is it talking about the present or the future?

Quando means when. Here it introduces a time clause for a habitual situation:

• … o meu olho dói quando estudo até tarde.
  → my eye hurts whenever I study until late

The tense:

• dói and estudo are both in the present,
• but they express a general, repeated situation, not necessarily something happening right now.

In Portuguese, this use of the present for habits and general truths is very common, just like English:

• Quando corro muito, fico cansado. – When I run a lot, I get tired.

What exactly does até tarde mean? Is it the same as até à tarde?

No, they are different.

• até tarde – until late (late at night / late in the day, vague)

  • Estudo até tarde. – I study until late.

• até à tarde – until the afternoon (until the time period called “the afternoon”)

  • Vou ficar aqui até à tarde. – I’ll stay here until the afternoon.

In your sentence:

• …quando estudo até tarde.
  means you stay up studying later than “normal” or “early” — often understood as late at night.

You can intensify it:

• …quando estudo até muito tarde. – when I study until very late.

Can I change the word order and say De vez em quando dói-me o olho quando estudo até tarde?

Yes, that is a very natural version in European Portuguese:

• De vez em quando dói-me o olho quando estudo até tarde.

Things to note:

• dói-me is the usual European placement of the clitic me (enclisis) after the verb, especially when the verb is in first position in the clause.
• The meaning is the same: From time to time my eye hurts when I study until late.

You could also say:

• De vez em quando, quando estudo até tarde, dói-me o olho.
  (a bit more formal / written, but clear and natural)

How is this sentence pronounced in European Portuguese?

A rough IPA transcription (European Portuguese) would be:

• De vez em quando o meu olho dói quando estudo até tarde.
  /dɨ ˈvez ẽ ˈkwɐ̃du u mew ˈɔʎu ˈdɔj ˈkwɐ̃du (ɨ)ʃˈtuðu ɐˈtɛ ˈtaɾðɨ/

Some helpful points:

• de → [dɨ], very short vowel; often sounds almost like d’
• vez em → often flows as vezem [ˈvez ẽ] in fast speech
• quando → [ˈkwɐ̃du]
• olho → [ˈɔʎu], with the lh sound (similar to Italian gli)
• dói → [ˈdɔj], one syllable, like doi with an open o
• Final e in tarde is [ɨ], very reduced: [ˈtaɾðɨ]

Spoken fast, it can sound something like:

• d’vezem quando o meu óleo dói quandoʃtudo até tard’ (very approximate in English spelling).