Eu não quero correr o risco de perder o ônibus.

Yes, you often can leave eu out in Portuguese.

Portuguese is a pro-drop language, which means the verb ending often already tells you who the subject is. In this sentence:

• quero = I want

So Eu não quero... and Não quero... can both mean I don’t want...

Including eu can:

• add emphasis
• make the subject extra clear
• sound more natural in some contexts

So all of these are possible, depending on context:

• Eu não quero correr o risco...
• Não quero correr o risco...

Both are correct.

In Portuguese, não normally goes directly before the verb it negates.

So:

• eu quero = I want
• eu não quero = I do not want

This is the standard word order for simple negation in Portuguese.

Compare:

• Eu falo português. = I speak Portuguese.
• Eu não falo português. = I do not speak Portuguese.

So não before quero is exactly what you should expect.

Yes, correr o risco is a very common expression.

Literally, it means something like to run the risk, which is very close to English. In natural English, we often say:

• to risk
• to run the risk of

So:

• correr o risco de perder o ônibus = to run the risk of missing the bus

This is a set phrase in Portuguese, and you will hear it a lot.

Examples:

• Você corre o risco de errar. = You run the risk of making a mistake.
• Eles correram o risco de perder tudo. = They risked losing everything.

Because the expression is correr o risco de + infinitive.

The structure is:

• correr o risco de fazer algo
• run the risk of doing something

So here:

• de perder o ônibus = of missing the bus

This de is required by the expression. You should learn it as one chunk:

• correr o risco de

Not:

• correr o risco perder ❌

In Portuguese, perder is the normal verb for to miss in the sense of fail to catch or not arrive in time for something.

So:

• perder o ônibus = miss the bus
• perder o trem = miss the train
• perder o voo = miss the flight

This is different from English, where miss has several meanings. Portuguese often uses different verbs depending on the situation.

For example:

• I miss you = Sinto sua falta or Estou com saudade de você
• I missed the bus = Perdi o ônibus

So perder here does not mean lose in the physical sense. It means miss in the transportation/schedule sense.

Portuguese uses definite articles much more often than English.

So where English says:

• miss the bus

Portuguese also says:

• perder o ônibus

In many contexts, Portuguese prefers the article even when English might omit it in other phrases.

Examples:

• Vou pegar o ônibus. = I’m going to take the bus.
• Ela perdeu o trem. = She missed the train.

Also, ônibus is a masculine noun, so the article is o.

In this sentence, ônibus is singular.

This is one of those nouns whose singular and plural have the same form:

• singular: o ônibus
• plural: os ônibus

You tell the difference by the article:

• o = the singular masculine
• os = the plural masculine

So:

• o ônibus = the bus
• os ônibus = the buses

Because after querer, Portuguese normally uses a bare infinitive, with no preposition.

Structure:

• querer + infinitive

So:

• quero correr = I want to run / I want to risk
• quero sair = I want to leave
• quero comer = I want to eat

The de in this sentence does not belong to quero. It belongs to the expression o risco de perder.

So the sentence breaks down like this:

• Eu não quero = I do not want
• correr o risco de perder o ônibus = to run the risk of missing the bus

Yes, that is possible, but it changes the phrasing a bit.

Compare:

• correr o risco de perder o ônibus
• arriscar perder o ônibus

Both can be understood as involving risk, but correr o risco de is a very common and natural expression for to run the risk of.

Also, be careful: arriscar perder o ônibus can sound a little less idiomatic in some situations than correr o risco de perder o ônibus, because the fixed phrase is very common for this exact meaning.

A very natural alternative would be:

• Eu não quero arriscar perder o ônibus.

That means something like:

• I don’t want to risk missing the bus.

So yes, arriscar works, but correr o risco de is especially useful to learn as a set pattern.

It is neutral and natural. You can use it in both everyday conversation and more careful speech.

Nothing in the sentence is especially slangy or especially formal:

• eu não quero = very common
• correr o risco de = standard expression
• perder o ônibus = everyday language

So it works well in normal spoken Brazilian Portuguese.

The full sentence is already natural, but in conversation Brazilians might sometimes simplify it a little:

• Não quero correr o risco de perder o ônibus.
• Não quero arriscar perder o ônibus.

Often the subject eu gets dropped unless it is needed for emphasis.

In pronunciation, spoken Brazilian Portuguese may also reduce some sounds:

• não quero may sound more connected
• de perder may sound like di perder in casual speech, depending on the speaker

But grammatically, the written sentence is perfectly natural as it is.

In Brazilian Portuguese, ônibus is pronounced approximately like:

• OH-nee-boos

A few notes:

• The ô is a closed o sound.
• The stress is on the first syllable: Ônibus
• The final s in many Brazilian accents sounds like an s sound, though pronunciation can vary by region.

A rough syllable breakdown:

• Ô-ni-bus

This word comes up often, so it is worth memorizing both the spelling and stress.