Eu não sei o que fazer hoje.

I don't know what to do today.

Breakdown of Eu não sei o que fazer hoje.

• eu: I
• hoje: today
• fazer: to do
• não: not
• o: the
• saber: to know
• que: what

Questions & Answers about Eu não sei o que fazer hoje.

Why is it o que and not just que in this sentence?

In this sentence, o que works together as “what” in an embedded clause:

• Eu não sei o que fazer hoje.
  I don’t know what to do today.

In European Portuguese:

• o que = what (as a pronoun, “the thing that”)
• que alone is usually that/which/that… as a conjunction, or part of other structures.

Here, o is a definite article (the) and que is a relative/interrogative pronoun; together they form something like “the thing that”, which in natural English is just “what”:

• (Eu não sei) o [que fazer hoje]
  → literally: “I do not know the [what to do today].”

If you said Eu não sei que fazer hoje, it would sound old‑fashioned / literary and is not what learners should use in everyday speech.

Why is fazer in the infinitive and not conjugated, like faço?

Here fazer is in the infinitive (to do) because it is part of the object of sei:

• Eu não sei [o que fazer hoje].
  → “I don’t know [what to do today].”

After saber (to know) in this type of structure, European Portuguese often uses an infinitive to express what action you don’t know how / whether / when to do:

• Não sei o que dizer. – I don’t know what to say.
• Não sei onde ir. – I don’t know where to go.
• Não sei que livro comprar. – I don’t know which book to buy.

Using a conjugated form like Eu não sei o que faço hoje means something different: more like

• “I don’t know what it is that I do today / what I’m doing today”
  (commenting on your schedule / behaviour), not simply “I don’t know what to do” as a decision.

Can I drop Eu and just say Não sei o que fazer hoje?

Yes.

Subject pronouns are often omitted in Portuguese when the verb ending already shows the subject:

• (Eu) não sei o que fazer hoje.

In speech, especially in European Portuguese, you will very often hear:

• Não sei o que fazer hoje.

Keeping Eu can add a bit of emphasis on I:

• Eu não sei o que fazer hoje.
  → I don’t know what to do today (maybe others do).

Where does não go? Could I say Eu sei não o que fazer hoje?

Não normally goes directly before the conjugated verb it negates:

• Eu não sei o que fazer hoje. – correct
  (não
  • sei)

Eu sei não o que fazer hoje is wrong in standard Portuguese.

Basic pattern:

• não + [conjugated verb] + (rest of sentence)

Examples:

• Eu não quero sair. – I don’t want to go out.
• Ela não gosta de café. – She doesn’t like coffee.
• Nós não podemos ajudar. – We cannot help.

Can I move hoje to another place in the sentence?

Yes. Time expressions like hoje are flexible. All of these are possible and natural, with slight differences in emphasis:

1. Eu não sei o que fazer hoje.
   → Neutral: “I don’t know what to do today.”

2. Hoje não sei o que fazer.
   → Emphasis on today: “Today I don’t know what to do.”

3. Eu hoje não sei o que fazer.
   → Also emphasizes hoje a bit, common in European Portuguese.

4. Não sei o que fazer hoje.
   → Quite common and natural, subject Eu omitted.

What you should not do is break up o que fazer:

• ✗ Eu não sei o que hoje fazer. – sounds wrong / very unnatural.

What is the difference between saber and conhecer? Could I say Eu não conheço o que fazer hoje?

Use saber here, not conhecer.

Rough guide:

• saber = to know information, facts, how to do something

  • Eu não sei o que fazer hoje. – I don’t know what to do today.
  • Ela sabe falar português. – She knows how to speak Portuguese.

• conhecer = to be familiar with / to know a person, place, or thing

  • Conheço Lisboa. – I know Lisbon / I’m familiar with Lisbon.
  • Não conheço esse livro. – I don’t know that book.

So:

• ✗ Eu não conheço o que fazer hoje. – incorrect / unnatural.
  You must say:
• ✓ Eu não sei o que fazer hoje.

Why is the verb saber conjugated as sei and not something like sabo?

Saber is irregular in the present tense. The 1st person singular (eu) form is:

• eu sei – I know

Key present forms of saber:

• eu sei – I know
• tu sabes – you know (singular, informal)
• ele / ela sabe – he/she knows
• nós sabemos – we know
• vocês sabem – you (plural) know
• eles / elas sabem – they know

So the correct form in the sentence is:

• Eu não sei o que fazer hoje.

This looks like a question inside a sentence. Why is there no question mark?

The sentence contains an indirect question, not a direct one.

• O que fazer hoje? – What to do today? → direct question (would take a question mark).
• Eu não sei o que fazer hoje. – I don’t know what to do today. → indirect question (embedded inside a statement).

In English we also do this:

• What should I do today? – direct question.
• I don’t know what I should do today. – indirect question, no question mark.

Portuguese works the same way: the whole sentence is a statement, so it ends with a period.

What is the difference between o que fazer hoje and o que vou fazer hoje / o que hei de fazer hoje?

All are possible, but they feel a bit different:

1. Eu não sei o que fazer hoje.

   • Very common and neutral.
   • Focuses on the available options / what action to take.

2. Eu não sei o que vou fazer hoje.

   • Literally: I don’t know what I am going to do today.
   • Feels more like you are unsure about your plans or schedule, not necessarily searching for ideas.

3. Eu não sei o que hei de fazer hoje.

   • More typical of European Portuguese; sounds quite natural, maybe a bit more “thoughtful” or slightly old‑fashioned.
   • Often used when you’re undecided or worried:
     
     • Não sei o que hei de fazer. – “I don’t know what I should do.”

All three can be correct, but Eu não sei o que fazer hoje is the simplest and most general for “I don’t know what to do today.”

Is it okay to say only Não sei o que fazer hoje in casual conversation?

Yes, absolutely.

Dropping Eu is very common and sounds natural:

• Não sei o que fazer hoje.

In a casual context, this may be even more frequent than the full version with Eu. The meaning is identical; the verb ending -ei in sei already shows the subject.

How do you pronounce Eu não sei o que fazer hoje in European Portuguese?

In careful European Portuguese, roughly:

• Eu não sei o que fazer hoje
  IPA (approx.): [ew nɐ̃w ˈsɐj u kɨ fɐˈzeɾ ˈoʒ(ɨ)]

Some key points:

• Eu – often sounds like [ew], sometimes very short, almost [e].
• não – nasal vowel [ɐ̃w]; the ão is nasal and ends in a light w sound.
• sei – like “say”, but a bit tenser: [sɐj].
• o – short [u] or [o] depending on accent; often quite reduced.
• que – usually [kɨ] in European Portuguese (very reduced vowel).
• fazer – [fɐˈzeɾ], with the final r pronounced (but weaker than in English).
• hoje – [ˈoʒ(ɨ)], the final e is often almost silent or very reduced.

In fast speech, you’ll hear linking and reduction:

• Sounds a bit like: [ew nɐ̃wˈsɐju kɨ fɐˈzeɾˈoʒ]
  (everything flowing together).

Can I capitalise eu in the middle of the sentence like in English I?

No.

In Portuguese, subject pronouns like eu, tu, ele, ela, etc. are not capitalised in the middle of a sentence, unless they start the sentence:

• Eu não sei o que fazer hoje. – at the start, Eu is capitalised.
• Disse que eu não sei o que fazer hoje. – in the middle, eu is lower‑case.

So you should write:

• Eu não sei o que fazer hoje.
  or (without the pronoun)
• Não sei o que fazer hoje.