'I didn't know what I should do'
In Spanish is this Really have trouble with the past in the past, especially writing essays.
No sabia(supe) lo que yo debia hacer?
Do you ever use the conditional in the past?
9 Answers
Because this sentence indicates something was or was not already done, you could use a gramatically correct structure by saying: No sabía que debería haber hecho (you didn´t know after something was/was not done) or "No sabía que debería hacer" (you didn´t know before/at the time something was/was not done).
However, the most common way is: No sabía que hacer (a slightly different nuance but in the end, the same meaning).
Along the same lines as my Spanish double negative post this is interesting as it highlights how we sometimes just work too hard to get it right in Spanish when in English we take shortcuts all the time.
The two sentences by Julian are: I didn't know what I should have done. And.... I didn't know what to do. In English we are most likely to say the second, or at last I am. So why do we complicate it when we go to translate to Spanish. Yes the nuance is slightly different but don't both get the point across?
Wait.
Is that correct?
I didn't know what I should do.
I would have said that as "I didn't know what I had to do" or "I didn't know what to do"
Edit:
I forgot to include that I would also say "I didn't know what I should have done"
2nd edit:
OK, I guess what threw me off was the title of the thread and the way it was translated.
But it all is fine now, as a matter of fact I look at it now and I see nothing wrong with it... I must have been sleeping or something... 
Thank you all.
Ahhhh! My favorite kind of question!!! Since Bosque put down most, if not all, of the examples given for discussion, I will use his as a stepping point.
"I didn't know what I should do." This would mean that I didn't know then what I should do now or in the future, like "When I spoke to you yesterday, I didn't know what I should do next weekend." It does not mean "I did not know (in the past) what I should have done (in the past)." I guess that would be the second example and answer.
"I didn't know what I ought to do." This is actually the same as above. I didn't know then what I ought to do now or in the future. Using the same format as above, the other way, with a different meaning, would be "I didn't know (in the past) what I ought to have done (in the past)."
"I didn't know what I was supposed to do." This would mean "I did not know in the past what I was supposed to do (at that moment in the past)." It sounds like preterite in the second clause to me.
"I didn't know what to do." Same as above, i.e., "I didn't know (in the past) what to do (at that moment in the past)." In this one, though, I would use the present tense in the second clause ("No sabía que hacer") (Or perhaps "... lo que hacer"?)
I hope this helps. 
RusselDunbar, should is not only used in the past. For example:
I am thinking about going to A or B, but I don't know which place I should go. Future.
Or using your sentence: I don't know if I should go or not. Present.
Any of the Americans natives can say something about this?
Very difficult for me, as all my grammar knowledge is of Spanis;, my English is almost completely instinct, unless I had to learn something atsome point to understand the Spanish.
I didn’t know what I should do. I can’t think of any reason it wouldn’t be correct, but I don’t think it is how I express it. I think it is conditional, and I think conditional can be used from a past referent.
I didn’t know what I ought to do. Sounds a little more familiar to me. I think still conditional. I think.
I didn’t know what I was supposed to do. Very familiar, I see myself saying that. I think now it is in an equivalent of the imperfect.
I didn’t know what to do. Also very natural for me. But it avoids the question.
If I pick a different concept, just because it is more familiar to me to express it: I didn’t know what would happen, I didn’t know what was going to happen, I didn’t know what might happen.
All three sound okay to me- I don’t know if the would in the first is conditional or imperfect (many times I don’t when I use would). I think the second is the equivalent of imperfect, the last I think is conditional.
I think in Spanish I could say "no sabía lo que iba a suceder" or "no sabía lo que sucedería" - the first imperfect and the second conditional. But I won't say that for absolute sure because I am an intermediate level learner.
These are my thoughts as someone who speaks English without understanding the grammar. Perhaps someone like Ian or AnnRon or someone else who does understand English grammar can chime in.
Hahah quiza no tenga un buen dominio de mi lengua nativa. Siempre usaría 'should' en el contexto del pasado, por ejemplo: ''I didn't know if I should go or not?''
Soy de irlanda, por lo tanto sea posible que es 'hibernización' de inglés.
You can say in English: I didn't know what I should do. This is correct but there are other more common ways to express it like: I didn't know what to do where the should part is implied rather than expressed (ie: the should part it is left unsaid but is understood from the context)
One of the major difficulties in determining what is considered grammatically good (acceptable) English is that we do not have an overall authority like the Spanish people do who have the R. A. E (Real Academia Española).
Language is constantly evolving and some of the grammatical do's and don'ts of good grammar that I remember being taught at school seem to have been thrown out the window long ago, like Never start a sentence with a conjunction, for example: and or but and always capitalise the word I Soem of these changes in practice have come from different editing standards used in the USA as American books have flooded the British markets, others have come from text type used by young teenagers
These constantly evolving standards can create some degree of confusion, combined with differing standards in spoken speech that vary from region to region in the U.K. and this patten is often repeated across other countries that share a similar language, (Spanish spoken in Spain vs Mexico or USA) so as different native speakers come together with different experiences, their ideas of acceptable language vary and this can result in misunderstanding, confusion and sometimes heated debates as to what constitutes good English, Spanish, French etc...
I hope that we can all accept that these regional variations are generally not bad but simply different....and perhaps outside of our current experience of a particular language , whether or not it is our native language. (I personally don't have problems with regional variations but I don't like the idea of Spanglish or Frenglish (lol) )
Any of the Americans natives can say something about this?
I ask, because English is my second language, and in instances like this I feel it isn't. :D
