Question

actions that are a one - time event must be conjugated in which tense?
neither
imperfect tense
preterit tense

Explanation:

The preterit tense is used for actions that are completed, often one - time events. The imperfect tense is for ongoing or habitual actions in the past. So one - time events are conjugated in the preterit tense.

Answer:

Preterit Tense