Sem você me avisar, eu não sei se devo puxar ou empurrar a porta.

Sem means without, and it is followed here by an infinitive phrase: você me avisar = you telling/warning me.

So:

• sem = without
• você me avisar = you informing me

Together, Sem você me avisar literally means Without you telling me.

This is a very natural way in Portuguese to express without someone doing something.

Because você is the subject of avisar.

Compare:

• Sem me avisar = Without telling me
  (it doesn’t clearly say who is doing the telling)
• Sem você me avisar = Without you telling me

So você is included to make it explicit that you are the one who should warn/inform me.

After a preposition like sem, Portuguese often uses the infinitive.

So the structure is:

• sem + infinitive

Examples:

• sem falar = without speaking
• sem pensar = without thinking
• sem você me avisar = without you telling me

This is very normal in Portuguese.

Also, this can be thought of as a case of the personal infinitive, although in você avisar the form looks the same as the regular infinitive. You can see it more clearly with other subjects:

• sem eu avisar
• sem nós avisarmos
• sem eles avisarem

Avisar usually means to tell, to inform, to warn, or to let someone know, depending on context.

Here, me means me, so:

• me avisar = to tell me / to let me know / to warn me

In this sentence, a natural English sense is without telling me or without letting me know.

In Brazilian Portuguese, placing object pronouns before the verb is very common, especially in everyday language.

So você me avisar sounds natural in Brazil.

You may also learn forms like:

• avisar-me

That is grammatically possible in some contexts and more associated with formal or European-style placement, but in Brazilian Portuguese me avisar is much more natural.

It means I don’t know whether/if.

Breakdown:

• eu = I
• não sei = don’t know
• se = if / whether

Here, se introduces an indirect question:

• eu não sei se devo... = I don’t know if/whether I should...

This se does not mean if in a conditional sense like if it rains; here it means whether.

In Portuguese, se often covers both if and whether in indirect questions.

So English distinguishes:

• I don’t know if...
• I don’t know whether...

Portuguese often uses just:

• não sei se...

Examples:

• Não sei se ele vem. = I don’t know if/whether he’s coming.
• Não sei se devo puxar ou empurrar. = I don’t know whether I should pull or push.

Devo is the first-person singular of dever.

Here, dever means should / ought to.

So:

• devo = I should
• não sei se devo = I don’t know if I should

Be careful: dever can also mean to owe, depending on context. But here it clearly means should.

Because Portuguese often omits subject pronouns when the verb form already makes the subject clear.

So both are possible:

• eu não sei se devo
• eu não sei se eu devo

The version without the second eu sounds smoother and more natural in many contexts.

Adding the second eu can give extra emphasis or contrast, but it is not necessary.

Because they depend on devo.

The structure is:

• devo + infinitive = I should + verb

So:

• devo puxar = I should pull
• devo empurrar = I should push

This is exactly like English modal-style structures.

Yes.

• puxar a porta = to pull the door
• empurrar a porta = to push the door

These are the normal verbs for that situation.

A learner might notice that English often says pull the door and push the door, and Portuguese works very similarly here.

Portuguese often uses the definite article where English may or may not use one.

So:

• a porta = the door

In this sentence, you are talking about a specific door, so a porta is completely natural.

Not with the same meaning.

• abrir a porta = to open the door
• puxar ou empurrar a porta = to pull or push the door

The point of the sentence is that the speaker does not know which direction/mechanism is needed. So puxar ou empurrar is much more precise than simply abrir.

Not exactly, although they can be similar in some contexts.

• Sem você me avisar = Without you telling me
• Se você não me avisar = If you don’t tell me

The first focuses on the absence of information.
The second is a more direct condition.

So the original sentence has a slightly more natural without your telling me feeling.

Yes, it is natural and correct.

Sem você me avisar, eu não sei se devo puxar ou empurrar a porta. sounds like something a Brazilian speaker could say.

It has a slightly careful or explicit tone, but it is perfectly normal.

A more conversational variant could also be:

• Se você não me avisar, eu não sei se devo puxar ou empurrar a porta.

Both are fine; the original is just structured a bit differently.

A close literal breakdown is:

• Sem = without
• você = you
• me = me
• avisar = to tell / inform
• eu = I
• não sei = do not know
• se = whether / if
• devo = I should
• puxar = pull
• ou = or
• empurrar = push
• a porta = the door

So a very literal rendering would be:

Without you informing me, I don’t know whether I should pull or push the door.

Yes, depending on nuance.

Possible alternatives include:

• dizer = to tell
• informar = to inform
• falar = to say / speak

For example:

• Sem você me dizer, eu não sei se devo puxar ou empurrar a porta.

This is understandable, but avisar is especially good because it suggests letting someone know in advance or giving them the needed information, which fits the situation very well.

In most of Brazil, yes, você is a very common way to say you.

However, depending on region, people may also use:

• tu
• cê (a spoken short form of você)

So you might also hear variants like:

• Sem tu me avisar...
• Sem cê me avisar...

But Sem você me avisar... is standard and widely understood throughout Brazil.