comienzan

In a sentence

• Los estudiantes comienzan sus clases a las ocho de la mañana.

  The students begin their classes at eight in the morning.

  The word 'comienzan' is used in its subjunctive form to denote the action of starting or beginning, relative to the students initiating their classes.

• Cada día comienzan a aprender algo nuevo en la escuela.

  Every day they begin to learn something new at school.

  Here, 'comienzan' signifies the habitual action of initiating the learning process in each day, describing a repetitive occurrence.

• Cuando suena la campana, los participantes comienzan la carrera.

  When the bell rings, the participants start the race.

  In this instance, 'comienzan' references the specific triggering action of starting a race, indicating the onset of an event prompted by an external signal.