Learn Hardcore Portuguese (Brazil): Eu preciso fechar a porta deste quarto.

precisar is far more common in everyday spoken Brazilian Portuguese to express “need.” necessitar exists but sounds formal or bureaucratic. You’ll hear preciso in casual conversation much more often than necessito.

What’s the difference between precisar de and precisar without de, and why don’t we have de after preciso here?

When precisar is followed by a noun, you need de:
• Eu preciso de um carro (I need a car).
But when it’s followed by an infinitive verb (another verb in its base form), you drop de:
• Eu preciso fechar a porta (I need to close the door).

Can I drop the subject pronoun eu and just say Preciso fechar a porta deste quarto?

Yes. Portuguese verb endings already tell you who’s acting, so preciso implies eu. Dropping eu is normal and even preferred in informal speech. You’d only keep eu for emphasis or clarity.

Why do we use fechar and not trancar for “closing” the door?

fechar simply means to close or shut. trancar means to lock (usually with a key or latch). If you just want the door shut, use fechar a porta. If you want it locked, use trancar a porta.

What does deste quarto mean? Why not just do quarto?

deste is a contraction of de + este (of this). It specifies this particular room (near the speaker). By contrast, do quarto (de + o) means of the room, without emphasizing “this” room. Use deste quarto when you want to point out “this room right here.”

What’s the difference between deste and desse?

Both are contractions with de, but:
• deste = de + este, “of this” (near me).
• desse = de + esse, “of that” (near you or previously mentioned).
Choose based on whose vicinity the room is in.

Could I say fechar a porta neste quarto instead of deste quarto?

You can, but it changes the preposition:
• neste quarto = em + este, “in this room.”
So fechar a porta neste quarto means “close the door in this room” (focus on location). deste quarto means “close the door of this room” (focus on possession).

Why is there an a before porta? Can you say fechar porta?

Standard Portuguese almost always uses a definite article before a specific noun. fechar a porta sounds natural; fechar porta without the article is ungrammatical in formal and most informal contexts. Some very colloquial or instructional signs might drop it, but you should keep a.