han comenzado a

have started to

→ haber
phrase Rare #23,769
have started to Used before an infinitive to say something has begun and is in progress.
SP: Los niños han comenzado a jugar en el parque.
EN: The children have started to play in the park.

Nadie puede detenerlos una vez que han comenzado a correr.

Nobody can stop them once they've started running.

— Nausicaä del valle del viento (1984)

Lo gorriones han comenzado a reconstruir.

The sparrows have begun to rebuild.

— It's Such a Beautiful Day (2012)

Las sirenas de emergencia han comenzado a sonar.

The emergency sirens have begun to sound.

— Memories of Murder (Crónica de un asesino en serie) (2003)