Learn Spanish (Latin America): Las puertas nunca se deben obstruir.

Las puertas nunca se deben obstruir.

The doors must never be obstructed.

Breakdown of Las puertas nunca se deben obstruir.

las

the (feminine plural)

(impersonal) one / passive marker

Questions & Answers about Las puertas nunca se deben obstruir.

Why is the verb deben in the plural here?

In this sentence, we are using the reflexive passive (pasiva refleja). Because it is a passive structure, the thing receiving the action—las puertas (the doors)—is actually the grammatical subject. Since las puertas is plural, the auxiliary verb deben must also be plural to match it.

How do I know this is the passive se and not the impersonal se (like "one must never obstruct")?

The key is subject-verb agreement. The impersonal se always takes a singular verb, regardless of what comes next in the sentence. Because deben is plural here to match las puertas, it has to be the passive se. If you wanted to use the impersonal "one", you would say Nunca se debe obstruir las puertas.

Could the se be attached to the end of obstruir?

Yes! When you have a conjugated verb followed by an infinitive (like deben obstruir), pronouns can either go right before the conjugated verb or attached to the end of the infinitive. So, Las puertas nunca deben obstruirse is perfectly correct and means exactly the same thing.

Could we change the word order and put las puertas at the end?