PRETERITE TENSE (Regular verbs) 1

-ar preterite endings — -ar verbs: -é, -aste, -ó, -amos, -asteis, -aron. Hablé, hablaste, habló, hablamos, hablasteis, hablaron. The yo and él/ella forms carry written accents (é, ó) to distinguish them from other tenses: hablé (I spoke) vs habla (he/she speaks / speak!).

-er/-ir preterite endings — -er/-ir verbs: -í, -iste, -ió, -imos, -isteis, -ieron. Comí, comiste, comió, comimos, comisteis, comieron. Note that nosotros is the same as the present for -ar verbs (hablamos) but differs for -er/-ir: comimos (preterite) vs comemos (present).

Preterite for completed, specific past events — The preterite is used when a past action is presented as a completed event — it happened and it's done. Key time signals: ayer, el lunes pasado, el año pasado, hace una hora, en 2010, por fin, de repente, una vez. If one of these appears in the sentence, the preterite is almost certainly the right tense.