Irregular verbs in the preterite tense in Spanish Irregular verbs don’t follow the usual pattern in the preterite tense. 'Ser' and 'ir' are conjugated in the same way in the preterite tense.

It is useful to learn these off by heart. Ser (to be) and ir (to go) have the same form in the past tense. Luckily, you can tell which one is being used from the context of the sentence. For example: ...