Preterite vs. Imperfect

[Tobyasha]

I took out my ancient high school Spanish textbook (copyright 1966!) and was working through the drills when I came across the exercise below. For some of the questions, the answer was pretty clear, but here are the ones I was unsure about.

Subráyase la forma correcta, según el significado de cada frase.
1. La orquesta (tocó, tocaba) el tango pero ellos bailaron el mambo.
2. Sospechaba que el testigo (mintió, mentía) cuando daba su testimonio.
3. En sus sueños aquella noche, el enfermo (vio, veía) sombras.
4. En la fábrica se (construyeron, construían) televisores cuando yo trabajaba allí.
5. El juez (creyó, creía) al señor que describió el incidente.

1. "Tocaba" was my first thought, but then again if "bailaron" is in preterite, then why not "tocó" as well?
2. In English both "he lied when giving his testimony" and "he was lying when giving his testimony" both seem perfectly okay. Is there a definite correct and incorrect answer here?
3. I have no idea here. Both seem reasonable.
4. I guess "construían" because this was an ongoing activity?
5. I guess the imperfect "creía" here too, but is "creyó" definitely wrong?

Thanks in advance for any advice you could give.

[Rusty]

The problem we English speakers have is that only one past tense exists in English.
Spanish has two.

The preterit is used when the action in the past had a start and an end in the past.
Ella fue de compras. (Done deal. She's back.)

Every other action in the past is habitual (recurring), ongoing (not finished yet, or interrupted), or repeated in the past. The imperative is also used to describe past events (a narration/retelling of things that haven't completed (are in process)).

I found it easier to remember 'happened' (started/ended, preterit) and 'was happening' (started, but not completed, imperfect).

1. (Did the tango start and end, or was it in process when the dancing of the mambo occurred in the past?)
2. (The judge was suspecting something when the witness was giving a statement in the past. This describes things that were happening. Why would the act of lying occur outside of these concurrent events?)
3. (Were the shadows seen once (started and ended) or were they happening (ongoing, recurring) over a period of time? It's likely, since a particular night is given, that the shadows weren't recurring or ongoing. They had a start and end in the past.)
4. (When the person was working at the company (narrative/story about something that was happening), did they start and stop building TV sets, or was this something the company was doing (recurring, repeated, or habitual) in the past?)
5. (Did the judge believe what was described by the man? There's no indication that his belief was interrupted. There's no reason to think that the judge always believed, kept believing, or used to believe the man. He believed him. That's it.)

I can see where it can be difficult to know for certain what the right answer is, since it is ultimately decided by the speaker when the sentence was formed, but we English speakers have to question whether the action clearly started and ended in the past, or not. If not, the imperfect is imperative.

[Tobyasha]

Thanks so much for your detailed reply. It has definitely given me an idea about what to think about when choosing between the two tenses.

If I've understood your comments for each question correctly, I suppose the answers that my textbook is looking for are:
1. tocaba
2. mintió
3. vio
4. construían
5. creyó

But I'm glad to know that for some questions, the opposite answer may be possible depending on interpretation/context.

[Rusty]

Good job!
I agree with each answer you came up with, but an argument for use of the imperfect tense can be given for the second sentence.

Your answer tells us that the witness lied (started and ended) during his testimony (at least once). Your answer could also be telling us that the testimony was fabricated beforehand (started and ended), before suspicion arose while the testimony was being spoken.
However, if the testimony was being created on the fly, at the same time the words were flowing and the unnamed person was becoming suspicious that the testimony contained falsehoods, then we can reasonably say that the witness was lying (mentía) during the delivery.

So, both answers could be correct, depending on what was happening at the time (depending on what your reasoning of the situation was). The Spanish-wired mind will understand the circumstance as it was framed (depending on the tense used). We English speakers have to use more words to understand whether there was a lie or a lot of lies, or whether the whole testimony sounded rehearsed, or fluid.