No obris el transportí a menys que el veterinari sigui aquí.

Because Catalan uses the present subjunctive for negative commands.

With obrir:

• Obre el transportí. = Open the carrier.
• No obris el transportí. = Don’t open the carrier.

So:

• obre = affirmative tu command
• obris = negative tu command

This is very common in Catalan and Spanish, and it often surprises English speakers.

The sentence is addressed to one person informally, so the hidden subject is tu.

Catalan often drops subject pronouns because the verb ending already shows who the subject is. Here, obris tells you it is tu.

So the full version would be:

• Tu no obris el transportí...

But Catalan normally leaves tu out unless it is needed for emphasis or contrast.

If you wanted other versions, you could say:

• No obri... = formal singular
• No obriu... = plural informal
• No obrin... = formal plural

Transportí means a pet carrier, especially the kind used to transport a cat or small dog.

In this sentence, it is most likely the carrier box or cage used to bring an animal to the vet.

A few useful notes:

• It is a masculine noun, so you get el transportí.
• It is a very practical, everyday word in contexts involving pets.

So el transportí here is not just any container; it specifically suggests an animal carrier.

A menys que means unless.

So:

• No obris el transportí a menys que el veterinari sigui aquí.
• = Don’t open the carrier unless the vet is here.

It is a fixed expression in Catalan. You should learn it as a chunk:

• a menys que = unless

It introduces an exception or condition under which the action would be allowed.

Because a menys que normally requires the subjunctive.

That is why Catalan uses:

• sigui and not és

Here is the contrast:

• El veterinari és aquí. = The vet is here.
• ...a menys que el veterinari sigui aquí. = ...unless the vet is here.

The second one is not stating a fact directly; it is expressing a condition, and that is why the subjunctive appears.

Also, sigui is the present subjunctive form of ser.

This is a very common question.

In Catalan, ser is often used where English speakers might expect to be in a location, especially when the idea is simple presence or being there.

So el veterinari sigui aquí means something like:

• the vet is here
• the vet is present
• the vet has arrived / is on hand

You may also hear estar aquí in some contexts and varieties, but ser aquí is perfectly natural and standard here.

A useful way to think about it is:

• ser aquí often sounds like simple presence
• estar aquí can sometimes emphasize actual location or temporary state a bit more

In this sentence, sigui aquí is the normal, idiomatic choice.

Because Catalan usually uses the definite article with nouns in places where English may or may not use one.

Here, el veterinari means the veterinarian / the vet. It refers to the specific vet relevant to the situation.

So:

• el veterinari = the vet

If it were a woman, you would say:

• la veterinària

This is completely normal in Catalan. The article is not optional here.

The written accent shows that the stress falls on the last syllable:

• trans-por-tí

The accent mark on í tells you the final syllable is stressed.

That matters because, without an accent, Catalan spelling rules would normally make you expect a different stress pattern.

So the accent helps you pronounce it correctly right away.

It can absolutely mean both, depending on how you translate it.

In English, the most natural translation in everyday speech is usually:

• the vet

But a more literal translation is:

• the veterinarian

So in this sentence, both are fine depending on tone:

• Don’t open the carrier unless the vet is here.
• Don’t open the carrier unless the veterinarian is here.

The Catalan word itself is veterinari.