Hola todos,

The following is an extract from a book entitled 'Breaking Out of Begginers Spanish' by Joseph Keenan.
I bought it a year and a bit ago, but am only now finding it somewhat useful. Here is an extract from the section on the subjunctive which I hope could help you all. Pretty much all of my understanding (which isn't saying too much...:P) of the subjunctive came from here. Disfruta!

...Spanish, of course, did not invent the subjunctive. In fact the subjunctive is widely used in English, though not nearly as frequently as it is in Spanish. Take, for example, a sign hanging in the Sears restroom in Waco, Texas - "It is important to us that our restrooms be clean". I nicer, neater subjunctive was never seen.

But in Spanish it’s often hard to get a feel for when the subjunctive is needed. The subjunctive gets the job of describing 'could-have-beens' 'might-bes' and 'maybe-never-weres'. Anything that has happened, is happening, or may happen on the borders of our conciousness gets handled by the subjunctive. The subjunctive is more than just a verb mode. It’s a completely different reality.

Indirect commands

This group covers giving orders, asking others to do things, and engaging in other bossy behaviour. Thus in a sentance like 'Tell the mariachis to go away' the English infinitive 'to go away' must be rendered in the subjunctive in Spanish. Why? Because the action of the mariachis going away doesn't become a reality until they actually go away. Until then, it must be considered entirely suspect notion. Will they go away? Will they stay? How about if we pay them?

We can lump implicit indirect commands in this category, including 'wishing' 'hoping' that the mariachis will go away.
'I hope the mariachis go away' is, after all just a cowardly version of saying 'Tell the mariachis to go away'. And, as in the first example, hoping is no garuntee that they will actually go. They may want to sing La Bamba again.
You have no way of knowing so you must rely on the subjunctive.

The Eternal Mystery

This is the realm of doubt, uncertainty, suspicion, and downright disbelief. For example, Es posible que los mariachis se vayan (It is possible that the mariachis will go.), Dudo que se vayan(I doubt that they will go). In each of these cases, we return to the elemental problem of the mariachis departure as uncertain. An action belonging to a seperate realm.
Statements of negotiation also occur in this shadowy world. But, arn't these statements of fact and should therefore belong in the indicative? On closer inspection, however, we see why they are here. Negotiations are declarations of something that never happened, actions that only exist in someone’s mind. Here, with a little study, we can see the careful distinction that turns a harmless, indicative statement, into an unruly, ethereal subjunctive.
No asalté el banco = I didn't rob the bank. Straightforward and indicative. I didn't do it. But when the sentance structure changes into a way that makes the action of a bank robbery stand alone, it acquires its true character-that of an action that was not. Niego que haya robado el banco = 'I deny that I robbed the bank.' Here, 'I robbed the bank' is a non event, an untrue claim, a load of nonsense. It simply didn't happen...I swear! And since it didn't happen, it must be exiled into a world where all things that never happened- the could-have-beens, the might-bes, the maybe-never-weres reside; the subjunctive.

A similar treatment awaits things that you 'Don't believe' or 'Don't think'. Since you don't believe them, you certainly don't have to consider them real. No creo que esté aqui = I don't think she's here. Here presence here is something that for you, the speaker, doesn't belong in your universe of hard facts. Thus, into the subjunctive it goes.

Non-Que cues

One use of the subjunctive is generally not introduced by que, so you'll have to be alert for it. Instead, it used cuando, done, como, and other adverbs. The best guide in this case is the english translation. When you could substitute '-ever' as in 'whenever' 'wherever' 'however', follow the adverb with the subjunctive in Spanish:

¿Cuando quieres ir? Cuando tu quieras. = When do you want to go? Whenever you want.

¿Adonde vamos? Donde quieras. = Where are we going? Wherever you want.

¿Cuando me vas dar el dinero? Cuando yo quiera. When are you going to give me the money? When I feel like it.

Once you get a feel for the Cuando quiera - donde quiera - como quirea complex, you will be close to mastering one of the trickiest uses of the subjunctive: A clause containing an adverb plus the subjunctive to refer to the future. For instance, in Spanish, you would say Cuando termine el libro, te llamaré for 'When I finish the book, I'll call you.
In this case, cuando is followed by the subjunctive because it refers to an event that may never happen. A meteor could strike the reader one page from the end, so the action of finishing the book remains uncertain.
Only when referring to habitual actions should you use the indactive. Cuando termino de leer el las mananas, voy a la tienda. 'When I finish reading in the mornings, I go to the store. The indactive is used because presumably this has happened before and will happen again in the future.

Travelers Subjunctive

A common question for lost, bewildered, or just curious travelers is as follows: 'Is there a such-and-such near here that does such-and-such?' For instance, 'Is there a shop near here that sells wine?'
In all cases like this you must use the subjunctive because you are not fully sure that they even exist (until the question is answered) For example;  Hay una tienda por aqui que venda vino?

I was listening to Marco Antonio Solís singing "Necesito una compañera" and it occurred to me that this song might help people learn the present subjunctive. The structure is:

     Necesito una compañera + que + adjective clause

The verb in the "que" clause is in the subjunctive because the speaker isn't talking about someone who necessarily exists; rather, he hopes she exists.

Chuckle all you want at the 80's style suits worn by the Bukis in the video, I think the song really holds up.  Check it out:

Los Bukis:  Necesito una compañera
 
Necesito una compañera,
que me ame y que en verdad me quiera
que no tenga maldad,
que en su alma tenga humanidad
que me sepa querer
sin temor a perder
 
Necesito una compañera,
que me ame y que en verdad me quiera
que me ayude a vivir
y que nunca nunca sepa mentir
que conozca el dolor
que valore el amor
 
Por que ya he sufrido tanto tanto
que hoy no puedo detener mi llanto
y no puedo callar mi soledad
¡Ay! qué soledad
la felicidad donde está yo la quiero encontrar (SE REPITE)
 
Por que ya he sufrido tanto tanto
que hoy no puedo detener mi llanto
y no puedo callar mi soledad
¡Ay! qué soledad
la felicidad donde está yo la quiero encontrar (SE REPITE)