There are various ways in Spanish to express an action in the past. This exercise treats the simple past, or PRETERIT, which means that a verb is a one-word verb, already completed, which took place only once. For example, "I sleep" is the present tense. "I slept" is the past tense. It is one word and the action is over. Formation: To conjugate IR verbs in the past drop the IR from the infinitive and you are left with ESCRIB, for example. Add the following endings to the stem: í, iste, ió, imos, istéis, and ieron. For example, ESCRIBIR in the preterit conjugates as follows: Escribí-I wrote Escribiste-You wrote Escribió-He,she, you (formal) wrote Escribimos-We wrote Escribistéis-You all wrote Escribieron-They wrote HOWEVER-Double stem change verbs are a bit different. You can recognize a double stem change verb in certain dictionaries or texts by the way they are listed. For example, if you search "dormir" it will probably have (ue, u) listed beside it. The "UE" lets the student know that this is an O-UE stem change verb in the present tense. The "U" that follows allows the student to know that in certain tenses, the U replaces the O from the infinitive. The preterit is one of those tenses. And the U ONLY overtakes the O in the third person, singular and plural. For example, DORMIR conjugates in the past tense as follows: Dormí Dormiste DURMIÓ (notice the U) Dormimos Dormistéis DURMIERON (notice the U) Frequently used verbs of this type are dormir (ue,u); pedir(i,i); repetir (i,i,); sentir (ie,i); prefeirir (ie,i); pedir (i,i); morir (ue, u); sentir (ie,i)and vestir (i,i) This change ONLY occurs in the 3rd persons. All others are taken directly from the infinitive. In the exercise provide the correct preterit conjugation.