Preterite and Imperfect summary

Preterite/Imperfect Usage
for a discussion on "aspect" (deciding which tense to use), please click here

Preterite

COMPLETED, DEFINED EVENTS WITH A BEGINNING AND/OR AN ENDING

A completed action (where the entire action is over at the point of reference mentioned.)
An action specifically referring to the beginning or the ending (It began to rain. / The parade ended at 4:00.)
An action specifically placed in time (Suddenly, at 1:00, on Monday, etc.). We know when the action began or ended
One specific case of an occurrence, rather than a recurring action.
A sudden change in the story (all of a sudden, I felt sad), even if it deals with emotion.
A repeating action specifically defined by the number of times done. (They went skiing six times)

Imperfect

FOCUSES ON DESCRIPTION, HABITUAL ACTIONS (used to, always, often) or ONGOING ACTIONS (was / were + ing - following "mientras" or another such term)

Any action where the point of reference occurs during the action (after the beginning or before the end) rather than at the beginning or at the end.
Descriptions in general: Appearance, age, physical condition, emotional state, attitudes, desires, location, date, time, weather
An action not specifically completed at the point of reference of the story
A continuous, habitual or repeated action where the moment of beginning or ending is not important. (happened multiple times, but we don’t know how many times)
Mental processes (thought, feeling, desire): creer, desear, querer, tener ganas de, pensar, preferir, poder, saber, etc.
An action told in the narrative: I was walking, it was raining, etc.
Something that used to happen. “I used to walk to school every morning.”

Key questions to ask yourself to determine between the preterite and the imperfect:

1. At this point in the story, does the verb refer to a specific, completed event? If it does, use the preterite (simple past). If it does not, or if it is unclear, use the imperfect. Remember, we have spoken of the preterite as a movie (where you can see the action from the beginning to the end) and the imperfect as a photograph (where you can see a moment in the middle of the action, but not the entire action.)

It was raining: no, imperfect
We often worked: no, imperfect
He ran: maybe...
He ran to the store: yes, preterite
He ran all Summer: no, imperfect
He felt sad: probably not, imperfect
The car didn't work: no, imperfect

It rained last night: yes, preterite
I studied hard yesterday: yes, preterite
We worked for 3 days: yes, preterite
They bought a new car: yes, preterite

2. Do you know when and how many times the specific event occurred? If so, use the preterite. If not, or if it is unclear or unimportant, use the imperfect. (This refers to an habitual action, rather than a completed event).

We skied once last winter: preterite (one time)
We skied a lot last winter: imperfect (many times)
I often thought about you: imperfect (???)
Yesterday, I thought, “I should call you.”: Preterite (one time, one specific thought)

3. Does the action in question advance the plot line or provide narration or background information? (Advance: Preterite, narration/background: Imperfect)

The man stole the purse and began to run. (Preterite: advances the action)
Grandpa invited everyone to come to our house. We all ate. (Preterite: advances)
It was a dark night and the wind was howling. (Imperfect: Background)
I didn’t know why I was going to her house, but I tried to have courage (Imperfect: narration)

4. Is the action in question specifically defined by time (and completeness?) If so, use the preterite.

It began to rain at 4:00       (Preterite)
It rained for 3 hours.       (Preterite)
It rained a lot last night.       (Imperfect)
It was raining yesterday.   (Imperfect)

Additional practice sites for using the preterite and imperfect tenses:

If you need help working on the irregular preterites, practice at www.conjuguemos.com
If you have not done the following, you may complete QUIZ #1 at each for up 10 pts. each (please write down which ones you complete in addition to submitting or printing them):

Practice with irregular preterites: www.phschool.com web code jdd-0513
More practice with preterite vs. imperfect (write down or print out your score for each of the following:) 10 POINTS EACH