use if the sentence is a single, completed action, and if the sentence passes this test: 1)The verb expresses an action 2)If yes, then ask: A)Is the action beginning? B)Has the action ended? C)Is the reference to the action a single occurrence?
"suddenly"; use the preterite tense
"immediately"; use the preterite tense
de golpe súbitamente
"all at once"; use the preterite tense
en ese momento
"then"; use the preterite tense
use if the verb is not an action verb, if the verb is a repeated action, or if the verb is a background action; "used to" indicates a repeated action; use with simultaneous action; use with age, time, weather, stories, thinking verbs, emotion