comenzaron a

began to

→ comenzar
phrase Uncommon #19,392
began to Used before an infinitive to say that something started happening.
SP: A las ocho comenzaron a llover.
EN: At eight o'clock, it started to rain.

Así que comenzaron a moverse hacia arriba.

So they began to move upwards.

— Masaan (2015)

Los tres comenzaron a reírse.

The three of them started laughing.

De pronto, comenzaron a gustarle las historias de detectives.

Suddenly, he began to like detective stories.

Comenzaron a discutir sobre Dios, y acabaron por perder la paciencia.

They began to argue about God, and ended up losing their patience.

— Fresas salvajes (1957)

De repente, ambos comenzaron a cantar.

Suddenly, they both started to sing.

Las estrellas comenzaron a aparecer.

The stars began to appear.

Los exploradores comenzaron a sufrir una severa escasez de comida.

The explorers began to suffer a severe food shortage.

Y entonces comenzaron a comerse unos a otros.

And then they started eating each other.

El otoño llegó y las hojas comenzaron a caer.

Autumn arrived and the leaves began to fall.

Las cosas comenzaron a tener sentido.

Things started to make sense.

Todas las huellas digitales locales comenzaron a llegar.

All the local fingerprints started coming in.

Las aves comenzaron a cantar por la mañana.

The birds began to sing in the morning.

Que comenzaron a morir muchos testigos.

That many witnesses began to die.

— Tropa de élite 2 (2010)

Los pájaros se escondieron entre las hojas y comenzaron a cantar.

The birds hid among the leaves and began to sing.

Los niños comenzaron a llorar.

The children began to cry.

Los científicos comenzaron a encontrar respuestas a estas cuestiones.

Scientists began to find answers to these questions.