Preterit and Imperfect: Is This Over Yet?

Written by tutor Emily R.

Differentiating between these tenses can be a little tricky at first, but once you understand the general difference, it’s really not so bad at all!

To begin, it is important to know that both the preterit and the imperfect are past tenses. The main factor that determines which to use to express a past-tense idea is whether or not the action has been completed. Any completed action regardless of its timeframe will be expressed using the preterit tense. The imperfect tense is utilized in cases of events that do not have a definitive end point. Simply by understanding this distinction, it should be much easier to decipher the tense. Use the following paragraph to see if you get it. Decide if the boldfaced words indicate a completed action (preterit) or an action that is not necessarily completed (imperfect).

It was a beautiful, sunny day. I was planting vegetables in the garden. I always used to plant tomatoes the Sunday after Mother’s Day. I was about to place a tomato plant in the hole when a mouse peeked its tiny head out of the hole. I screamed and dropped the plant…

How did you do? You should have identified the first four verbs as imperfect and the next three as preterit. Here’s why…

It was a beautiful, sunny day. How do we know that the day is over?
I was planting vegetables in the garden. Could I still be planting vegetables?
I always used to plant tomatoes… Could I still plant tomatoes on that date?
I was about to place a tomato plant in the hole. Did I complete that action?

The answer to each of these questions should tell us that the actions have not yet been completed. If you had trouble with this, you may have been adding your own knowledge to the information provided. Treat each sentence as its own entity and do not make assumptions. The second sentence ends with I was planting vegetables in the garden. At this point in the story, we know nothing about the mouse or the dropped plant. Evaluate the verb when you reach the period at the end of the sentence, not at the end of the paragraph. Does that make more sense? Good!

As a general rule, the imperfect is used to set the stage for a story. It often translates as was ___ing or used to ___, which should indicate an action in progress or a pattern of events that has not necessarily ended. To clarify a commonly asked question, used to does not indicate that the action no longer happens. It indicates repetition, and repeated events in the past are expressed by using the imperfect tense. Additionally, age, weather conditions expressed with hacer, and the time on the clock take the imperfect and will be expressed with the correct forms of tener, hacer, and ser, respectively.

Now let’s explore the preterit…

A mouse peeked out of the hole… Did the head rise above the hole?
I screamedDid the sound leave my mouth?
And dropped the plant. Did the plant leave my hands?

These actions have all been completed. Any completed action or a series of them requires the preterit tense.

If you have trouble with this concept, try to visualize the statements in order to tell if the action within each one has been completed. Use the following two sentences to illustrate.

Mark was crossing the road…
Mark crossed the road.

In the first example, you should visualize Mark in the road moving in the direction of the other side. He has not reached the other side, meaning that this is an incomplete action (imperfect). When you visualize the second statement, Mark should have reached the other side, thus completing the action (preterit).

Here is a fine point that may come up in more advanced study. When dealing with feelings and emotions, use the imperfect to express how a person was feeling in general and the preterit to pose a reaction to a stimulus or change in emotional state. Estaba cansada means that I was feeling tired. Estuve confundida indicates that something made me confused.

So to summarize the difference between the two tenses, when telling a story in the past, use the imperfect to set the stage, to express patterns of events or actions in progress, and to tell age with tener, weather with hacer, and time with ser. Use the preterit for completed actions. Got it?

But, what happens when we take away the context of a story? Many teachers quiz this concept with individual sentences. This means that you have to look for indications of completion in each example. Use the imperfect when you see expressions that indicate repetition like siempre, todos los días, cada __, or muchas veces. Use the preterit when there is a limited timeframe or an indication of completion as indicated by anoche, el verano pasado, de repente, or por tres semanas.

Preterit and Imperfect Quiz

Mi mamá ___ al mercado los lunes.

The correct answer here would be B.

Los lunes indicates repetition. There is nothing to indicate that this pattern has been broken; therefore, this could still be happening each Monday.

Yo _____ por dos horas.

The correct answer here would be A.

Por dos horas is a timeframe with a definite start and end, so the preterit must be used.

Tú _____ muchos poemas cuando eras joven.

The correct answer here would be B.

Cuando eras joven is an indefinite timeframe. Plus, you may still write poems.

Cada verano mi familia y yo _____ a mis abuelos.

The correct answer here would be B.

Cada verano, like #1, indicates a repeated action whose pattern may still be occurring.

Hopefully this has helped to distinguish between the uses of the preterit and imperfect. Good luck!

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