Which subjunctive?

[Hiperbólico]

I think I left the oven on.

Creo que deje / dejara el horno encendido.

I know the second clause contains a subjunctive as per the uncertainty, but I'm not sure which tense to use. I thought one should only use the imperfect subjunctive when the first clause contains the preterit or imperfect. However, the present subjunctive doesn't sound right nor does it match up well with the English version.

[aleCcowaN]

Creo que deje el horno encendido
Creo que dejara el horno encendido
Creo que dejé el horno encendido

You think so / you think not ---> indicative
You don't think so ---> subjunctive

Creo que dejé el horno encendido
Creo que no dejé el horno encendido
No creo que [haya dejado/dejara] el horno encendido

[Hiperbólico]

Creo que dejé el horno encendido
Creo que no dejé el horno encendido
No creo que [haya dejado/dejara] el horno encendido

Ah, thanks. I should've checked my reference: indicative for creer, pensar, etc. and subjunctive for no creer, no pensar, etc. Considering my other inconsistencies with el subjuntivo, I really should've dedicated more attention to it in class. :duh:

En fin, ¡gracias!

[fusekisan]

Hiperbólico:
There is no subjunctive in your examples, at all :)
If you say "que dejé" means "that I left" (an accomplished fact, even if you are not sure that that was the case).
If you say "dejará", you are saying (oddly enough): "I think that he/she will leave the oven on" (forecasting catastrophy).

You would use subjunctive in the negative forms of the sentence: "No creo que deje...).

Note the the crucial importance of the "tilde" (the graphic accent) in these cases.

Saludos.
Luis

Sanz Irles
Escritor