ellos corrían

they ran, they were running

→ correr
corr run + ían 3rd person plural imperfect (indicative or subjunctive)
verb · third plural · imperfect indicative Rare #45,827
they ran, they were running
SP: Los niños corrían por el parque.
EN: The children were running through the park.
Conjugation of correr
Indicative imperfect
SingularPlural
First corría —
Third corría corrían
Subjunctive imperfect
SingularPlural
First corría —
Third corría corrían

El grupo de payasos comenzó a tropezar mientras corrían.

The group of clowns began to stumble as they ran.

Especialmente cuando corrían entre ellos.

Especially when they were running among themselves.

— Senna (2010)

Recuerdo que todos corrían ese día..

I remember that everyone was running that day.

— Las flores de la guerra (2011)

Lágrimas corrían por sus mejillas.

Tears ran down her cheeks.