There are many verbs that are irregular in the preterite. Their forms must be memorized.

DAR

di, diste, dio, dimos, disteis, dieron

IR

fui, fuiste, fue, fuimos, fuisteis, fueron

SER

fui, fuiste, fue, fuimos, fuisteis, fueron

The rest of the irregular verbs share the preterite endings -e, -iste, -o, -imos, -isteis, -ieron. Notice that none of the endings have accent marks. For these verbs you can learn the irregular preterite stem and use the appropriate endings. NOTE: The third person singular form of hacer has a spelling change of c > z: hizo. Also, the third person plural form of decir and traer does not use the -i- of the ending: dijeron, trajeron.
 

Examples of Preterite: Irregular Verbs

• Me dijeron que el viaje a Acapulco es agradable
• Roberto me dijo que algunas de estas excursiones son muy interesantes.