I need some refreshing on the differences between preterit and imperfect preterit tenses of the verb saber.

I understand the following connotations:

  • saber -- To know (or to taste)
  • , sabes, sabe -- Present (I know, you know, he knows)
  • sabré, sabrás, sabrá -- Future (I will know, you will know, he will know)

But what are the different connotations with the past tenses:

  • sabía, sabías, sabía -- imperfect preterit
  • supe, supiste, supo -- [simple] preterit

With many verbs, the preterit and imperfect translate roughly to "I did X" (a distinct, completed action) and "I was doing X" (an ongoing action), but in the case of a verb like saber, one cannot know something in the former sense of "I knew it, then I finished knowing it" (without severe medical trauma).

So what do these past-tense forms of saber mean? What are the connotations?

3 Answers 3


Speaking from an intuitive point of view, the first one:

  • sabía, sabías, sabía...

is roughly equivalent to the English 'I used to know', an example sentence would be:

Yo sabía hablar español (I used to know how to speak Spanish).

Here you knew something but maybe forgot due to lack of practice.

The second one:

  • supe, supiste, supo

means 'I knew', an example sentence would be:

Yo supe la respuesta correcta (I knew the right answer).

So, as you can see, in the first case you could have known something but then forgotten it, and in the second case it implies that you knew something at the time when it was needed.

There might be other connotations but these are the two most obvious ones that spring to mind.


The first thing to say is that there is no one-to-one correspondence between the tense/aspect/mood of Spanish and English verbs.

Whereas English has only one simple past, Spanish has two: pretérito simple and pretérito imperfecto.

In general, one can translate both the pretérito simple and pretérito imperfecto into simple past. In many cases the context is enough to ensure no information is lost in the translation.

However, when translating the English simple past into Spanish, one has to decide which choice, pretérito simple or pretérito imperfecto, is more appropriate.

The criterium for this choice is what it is called in grammar the perfect aspect as I will explain next.

Both the pretérito simple and the pretérito imperfecto are past tenses, and hence, they describe actions that took place in the past. However, whereas:

  • the pretérito imperfecto (sabía, sabías, sabía...) has not perfect aspect,

  • the pretérito simple (supe, supiste, supo...) has perfect aspect and this means the action described by the verb not only took place in the past, but also happened before another event in the past. Hence, it is not appropriate to use pretérito simple unless the context provides this additional reference in the past.

OK, the explanation above is pretty abstract, let's borrow Zane's example to see how it works:

I did not know that school started at 9:00am today.

In principle, there would be two possible translations:

No sabía que la escuela empezaba hoy a las 9:00 (pretérito imperfecto)

Without additional context, I believe the pretérito imperfecto is the most appropriate translation. It simply states that, at some point in the past, you didn't know something.

Without additional context, the use of pretérito simple sounds incorrect:

No supe que la escuela empezaba hoy a las 9:00 (pretérito simple)

However, if the sentence is completed with additional context defining another event in the past, then the use of pretérito simple becomes the most appropriate choice:

No supe que la escuela empezaba hoy a las 9:00 hasta que tú me lo dijiste (pretérito simple)

Note that "tú me lo dijiste" is also pretérito simple, but explaining this choice of tense deserves another question.



No sabíamos que tú eras Superman

We didn't know you were Superman

This sentence has no definite termination point. How long did the subjects of the sentence not know this? A decade, a year, a minute? Saber is a verb often conjugated in the imperfect in its usage. It's difficult to compare/translate it to English, because in English, when we know the termination point, we find out. It's very close in meaning to the verb aprender at this point.

I did not know that school started at 9:00am today.

A ) Yo no sabía que hoy la escuela se comeinza a las 9.

B ) Yo no supe que hoy la escuela se comienza a las 9.

The first sentence is like saying, I wasn't aware, I had no clue While B would mean that you did not find out, as if you were frantically searching for the fact that school started at 9am that day. If you were just starting your semester courses and did not make an effort to even learn what times they started, then you could get away with saying B because a person cannot continue to not know something (unless they have a mental disorder) after having found out. You only need to touch a hot stove eye once to know that it will hurt you. Otherwise, you would use A, and most of the time you are going to use A, because it is part of that group of verbs that includes querrer, poder, and conocer.

Just remember that when you use the preterite tense, you are conveying an action performed once, in the past, at a specific time in space. Comí la comida doesn't just mean that I ate the food in the past, but rather that I ate it once.

Me comí la comida would mean that I ate all of the food, once. But that difference is not relevant.

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