Start with the third person plural (they) preterite form and take off -ron ending. Then add the endings below. Both "-ra" and "-se" endings can be used - "-ra" is a bit more common.
| Subject | -AR, -ER, -IR Verbs (-ra endings) | -AR, -ER, -IR Verbs (-se endings) |
|---|---|---|
| Yo (I) | -ara | -ase |
| Tú (You) | -aras | -ases |
| Él/Ella/Usted (He/She/You formal) | -ara | -ase |
| Nosotros/as (We) | -áramos | -ásemos |
| Vosotros/as (You plural informal) | -arais | -aseis |
| Ellos/Ellas/Ustedes (They/You plural formal) | -aran | -asen |