| A | B |
| habitual or repeated actions (used to) | use the imperfect |
| one-time simple actions | use the preterite |
| age | use the imperfect |
| location | use the imperfect |
| defined time periods | use the preterite |
| physical conditions | use the imperfect |
| emotional states | use the imperfect |
| attitudes or desires | use the imperfect |
| interuption of an ongoing action | use the preterite |
| time | use the imperfect |
| weather | use the imperfect |
| continuous actions in the past (completion of the action is unkown) | use the imperfect |
| appearance | use the imperfect |
| los/las + time expression | ON/THE ex: los lunes = on mondays los veranos=in the summers - use the imperfect |
| todos/todas + time expression | all/every example:todos los días=everyday todos los veranos=every summer - use the imperfect |
| a veces | sometimes - use the imperfect |
| nunca | never - use the imperfect |
| siempre | always - use the imperfect |
| cada + time expression | each/every example: cada tarde=every afternoon - use the imperfect |
| de vez en cuando | once in a while - use the imperfect |
| con frecuencia | frequently - use the imperfect |
| frecuentemente | frequently - use the imperfect |
| el/la + time expression + pasado(a) | ON .../THE... example: el mes pasado=last month la semana pasada=last week - use the preterite |
| por + number + time expression | for ...example: por dos horas=for two hours - use the preterite |
| ayer | yesterday - use the preterite |
| ayer + time expression | yesterday ...example:ayer por la tarde=yesterday afternoon - use the preterite |
| anteayer | the day before yesterday - use the preterite |
| anoche | last night - use the preterite |
| una vez | one time - use the preterite |
| esta/este + time expression | this ...example: esta mañana=this morning - use the preterite |