Answer:
preterito is used for past actions that are completed and imperfecto is used for past actions that didn't have a start or end
examples
imperfect
repetitive action
something u used to do
time or age
talking about the future
preterito
how long it occurred
took place at a certain time
start of a event
completed actions
“ella empezó a cocinar”
hope this helps :)
Él es un adverbio (cumple la función de un sustantivo en la frase).
Juan no quiso jugar → Él (adverebio que sustituye "Juan") no quiso jugar
Hope it helped,
BioTeacher101