Preterit vs. Past Perfect

[laepelba]

As I look through all of these exercises that I have been doing so poorly with lately, I see that I am making many mistakes with the "past perfect".

Some examples of sentences that I conjugated incorrectly:

- Así fue en efecto, porque cuando se graduó, él obtuvo un puesto que le pagaba el doble de lo que habría ganado si no se hubiera graduado. (I wrote "graduara".)

- Un día, cuando sus padres regresaron del trabajo, les sorprendió que Tomás ya hubiera preparado la cena para toda la familia y que la mesa estuviera puesta. (I wrote "preparara".)

- Cuando don Eugenio quería que las enfermeras le dieran de alta en el hospital, ellas le dijeron que llenara unos formularios y que leyera con cuidado las instrucciones que tenía que seguir en cuanto a cómo y cúando tomar los medicamentos que su médico había recetado el día anterior. (I wrote "recetó".)

- Lo que sí le pesaba era que el médico le hubiera indicado que su condición le obligaría a seguir tomando ciertos medicamentos para siempre. (I wrote "indicara".)

- Un día, para agradar a su hijo, después de que todos habían comido, don Eugenio decidió que era importante que ellas vieran un programa educativo en la tele. (I wrote "comieron".)

- ¿Te has preguntado alguna vez cómo sería el mundo si el automóvil jamás hubiera sido inventado? (I know this one is a bit different than the others. I wrote "hubiera existido".)

Can someone help me see what it is that I am missing every time? THANK YOU!!!

[wrholt]

The last sentence is a different case, so I will ignore it for the moment, and talk about it later.

All of the sentences in which you used a simple past tense (preterite, imperfect, or past subjunctive) instead of a perfect tense (pluperfect indicate, pluperfect subjunctive) deal with events in relation to some specific time in the past.

The perfect tenses refer to events that occurred (or failed to occur) BEFORE the time in question. The simple past tenses refer to events that occurred (or failed to occur) AT the time in question. The conditional tense refers to events the might occur AFTER the time in question.

You kept using the simple tenses, which places the events AT the time of the sentences. However, those events actually happened BEFORE the time of the sentences, and the only way to place a past event BEFORE another past event is to use a pluperfect verb.

The last sentence is different: you correctly chose a pluperfect subjunctive, and you happened to choose a different main verb (existir [active voice]) than the answer that was given (inventar as ser inventado [passive voice]). Unless there was something in the exercise to suggest that you should choose inventar (ser inventado) instead of existir, in my opinion what you chose is an acceptable sentence.

[laepelba]

That makes a lot of sense! So I missed the context, by just looking at one simple phrase.... Thank you!!